Common Core Standards & Domains

What is Common Core?

The Common Core is a set of high-quality academic standards in mathematics and English language arts/literacy (ELA). These learning goals outline what a student should know and be able to do at the end of each grade. These standards establish what students should know by the end of the year, but do not dictate how teachers should teach. The standards were created to ensure that all students graduate from high school with the skills and knowledge necessary to succeed in college, career, and life, regardless of where they live. Forty-two states have voluntarily adopted and are moving forward with the Common Core.

Learn more about Common Core at

What Are the Common Core Domains?

Common Core standards are broken into groups called “domains.” In elementary school (Kindergarten through 5th Grade), there are four primary domains:

Numbers & Operations

Numbers & Operations refers to the math skills often thought of as arithmetic, from reading and writing numbers to adding, subtracting, multiplying and dividing different types of numbers. As students progress, this comes to include whole numbers, decimals, fractions, integers, and irrational numbers. Sub-domains include:

  • Counting & Cardinality (K only) - Number names, counting, and comparing numbers
  • Numbers & Operations in Base 10 (K - 5th Grades)
  • Fractions (3rd - 5th Grades)
Algebraic Thinking

Algebraic Thinking refers to math skills related to seeing number patterns, understanding the meaning of addition, subtraction, multiplication and division, and using symbols to write and solve equations including those used to solve word problems.

Measurement & Data

Measurement & Data represents a wide range of math skills related to collecting, organizing, and interpreting numerical information, from telling time or using a ruler to measure the length of an object to using formulas to find volume or surface area. It also includes understanding tables and graphs, and in later grades, statistics and probability.


Geometry refers to a variety of skills related to analyzing two- and three-dimensional shapes. These include naming and classifying shapes using characteristics such as symmetry, number of sides, and angle measures, and in later grades, using congruence and similarity.

Back to Top


What is iReady?

iReady is an online instructional and diagnostic tool for reading and math that is aligned with the Common Core standards. Developed by Curriculum Associates, iReady is currently used by approximately one million students. iReady’s diagnostic tool pinpoints students’ needs down to the sub-skill level, and then provides personalized student instruction targeted to students’ unique areas of needs to boost achievement, as well as data for educators with real-time insights for each student.

iReady’s diagnostic tool checks students’ skills in each domain, and then provides an individualized “playlist” of online lessons for each student in each domain. Each online lesson is designed to be both challenging and engaging. iReady delivers instruction using engaging, contemporary animation; the lessons are also interactive. Lessons consist of a tutorial and practice and are followed by a short check for understanding. The result is an experience that attracts and holds the child’s interest while also teaching important skills and concepts. These lessons are proven to help students grow academically.

How is iReady Used in the 2 Sigma Model?

The 2 Sigma model is built around the goal of maximizing the quantity and quality of time teachers spend working with students one-on-one and in small groups. While teachers work with some students, others work on the computer engaging with one of several personalized online tools (including iReady). Teachers check in with students on the computer to make sure they are focused and to answer any questions they may have. The students then rotate, and those who were on the computers have the opportunity to work in small groups with a teacher. Depending on the grade level and teacher, each rotation lasts 15-25 minutes.

How Often is Iready Used?

Although math rotations happen every day, iReady Math is used only 2-3 times per week so students can work with other programs the rest of the week. Lessons vary in estimated duration (anywhere from 2-40 minutes), and students vary in how quickly or slowly they move through any given lesson. Students who complete a lesson immediately move on to the next lesson in their “playlist.” Students who are in the middle of the lesson at the end of the 15-25 minute rotation continue are considered “in progress” and will continue where they left off in their next iReady session.

Who Decides Which Lessons a Student Should Do?

Each lesson in iReady is assigned a level of difficulty, broken down into “Early K,” “Mid K,” “Late K,” and so on. Based on iReady’s diagnostic tool, each student is placed at one of these levels in each domain. A student’s diagnostic level determines which lessons are added to the student’s personal lesson playlist. These levels are independent of each other, and it is not uncommon for a student in a particular grade to be assigned lessons that are on, above, and below grade level in different domains.

Once a student completes the lessons in one level in a particular domain, the lessons from the following level will be added to the playlist. If a student is behind in one or more domains, catching up in those domains will receive priority over moving ahead in other domains. When there is a “tie,” the foundational domains of Numbers & Operations and Algebraic Thinking generally are prioritized. On top of iReady’s automated sequence, teachers are also able to assign specific iReady lessons to students at any level at any time.

How Does iReady Connect with What the Teacher is Teaching?

Because all of the offline and online math content being used in a 2 Sigma classroom (including iReady) is aligned to the Common Core standards, students are being engaged through different modalities to achieve the same, clear learning goals. Each student has his or her own personal lesson plan, which means that one student may be reviewing concepts previously taught by the teacher, a second student may be practicing the concept currently being taught by the teacher, and a third student may be previewing a concept that teacher will cover later in the year.

In addition to daily check-ins, teachers receive a customized report from 2 Sigma each weekend with all of their students’ iReady lessons and performance for the prior week. Teachers receive training from 2 Sigma on reviewing this data and following up with students accordingly.

On top of iReady’s automated sequence, teachers are also able to assign specific iReady lessons to students at any level at any time.

Back to Top

Tracking Progress

How is Progress Tracked in iReady?

Each time a student completes a lesson in iReady, the student is assessed on the skills that were presented in that lesson. Although the assessment is interactive and may not feel like a quiz, data is collected on how the student performs. If a student demonstrates proficiency on the assessment, the lesson receives a passing score and is added to the student’s list of passed lessons in that domain. Once the student completes all lessons for one level of a particular domain, the level is considered complete.

Is there More Information on a Student's Performance on a Lesson?

The most important information is whether or not the student demonstrated proficiency by receiving a passing score on the assessment. There are also a number of possible notifications included in the report that provide additional relevant information.

How Many Lessons Are There at Each Level?

There is a wide variety in terms of how many lessons exist in each level in a particular domain. Some concepts are more straightforward and can be presented in one or two lessons. Other, more complex concepts require more lessons in order to break the learning into small pieces and assess the student at each step of the way. Additionally, some domains or concepts are typically taught at different times of the year rather than others because they are dependent on certain prerequisite skills in the same or other domains. As a result, some domains may have significantly more lessons at one level than another.

What is the iReady Domain Progress Chart?

The iReady domain progress charts provide an overview of the student’s progress in each domain so far this year. The charts include information about the student’s original level, current level, and progress made to date in the current year and month.

Here is an example of a Geometry progress chart with a legend below. Each box represents one level (there are three per grade level - “early,” “mid,” and “late”):


Example: the graph above indicates that the student placed at a Mid 1st Grade level in Geometry in the diagnostic, meaning that all levels up to and including Early 1st Grade were not included in the lesson plan. Since the beginning of the year, the student has completed two levels in geometry (Mid 1st Grade and Late 1st Grade). The Late 1st Grade level was completed this month.

Back to Top


What are Notifications?

Notifications are a way to provide more information about a student’s activity related to a particular lesson. There are three types of notifications:

  1. A notification that indicates that the lesson was assigned by the teacher (separate from iReady’s auto-generated personalized playlist)
  2. A notification that indicates performance that was particularly high or low within the passing range
  3. A notification that indicates if the student completed the lesson particularly quickly or slowly

What is a Teacher-Assigned Lesson?

One of the advanced features of iReady is that it allows teachers to assign lessons to students at any level separately from the auto-generated playlist. This includes lessons that are part of the automated sequence, as well as “supplemental” lessons (which have a grade level but no “early,” “mid,” or “late”) that would not have otherwise been assigned. Teachers can choose to assign a particular lesson to an entire class, a group of students, or an individual student. There are many different goals a teacher may have in assigning a lesson, for example:

  • Practice: A teacher may assign a lesson to give students more practice with a challenging concept being taught in class
  • Review: A teacher may assign a lesson to see which students may need to review earlier concepts before building on top of them
  • Preview: A teacher may assign a lesson to give students a preview of upcoming concepts

Depending on the circumstances, a teacher may choose to assign a lesson that is on, below, or above the student’s grade level and/or current iReady level.

What Are the Different Levels of Performance?

A student must receive a passing score on the assessment at the end of a lesson in order for the lesson to appear in the list of “lessons passed” in each domain (hurdles and struggles are shown in later sections of the report). A passing grade indicates that the student has satisfactorily demonstrated proficiency in that particular skill. The student will then move on to the next lesson in his or her personalized lesson plan.

Each iReady assessment has a defined level of performance that sets the boundary between passing and not passing. As far as iReady is concerned, any student who exceeds that level of performance has demonstrated proficiency and should move on to the next lesson. However, 2 Sigma’s experience has been that students who achieve a passing score fall into different categories and further analysis can better describe a student’s performance and possible next steps.

In order to provide further detail, there are two possible notifications related to performance that may be seen next to a lesson in the report:

  • The student demonstrated mastery of the skill by performing at a perfect or near-perfect level
  • The student passed the iReady lesson but deeper analysis indicates that the student may still benefit from further review

If 2 Sigma’s analysis indicates that the student would still benefit from further review, the teacher receives an alert in the weekly iReady report. The teacher will then check in with the student, and will decide whether or not to review the concept in question and/or re-assign the lesson in question so the student can achieve a greater level of proficiency.

What Are Speed Notifications?

For each lesson, iReady provides an estimated amount of time it takes the average student to complete that lesson. Students naturally move more quickly or more slowly, but most students complete most lessons within a certain range around the average. Most of the time, there is nothing to report. Sometimes, however, students complete a lesson particularly quickly or slowly. In those cases, a notification is provided.

What if there are no notifications for a particular lesson?

If there are no notifications, that means that:

  • The lesson was assigned to the student by iReady’s auto-generated lesson plan (as opposed to the teacher)
  • The student completed the lesson within the expected range of time
  • The student has satisfactorily demonstrated proficiency in that particular skill

Back to Top

Hurdles & Struggles

What Happens if a Student Doesn’t Pass a Lesson?

Just as with face-to-face teaching, there are times when a student doesn’t internalize a concept the first time it is presented. With an iReady lesson, that lack of understanding can be identified just a few minutes later when the student is unable to demonstrate proficiency on the assessment. Many times, the student just needs a bit more time to fully digest what is being presented. In these scenarios, research recommends “reteaching,” which is the practice of simply presenting the material a second time. The strategy of reteaching is (sometimes surprisingly) effective and is often used in intervention and special education settings.

iReady uses a reteaching approach to students who do not demonstrate proficiency on the first try. If a student completes the assessment and does not demonstrate proficiency, the lesson is immediately re-assigned to the student in the hope that the second time will be the charm.

What is a "Hurdle?"

A “hurdle” is when a student does not demonstrate proficiency on an assessment, is then re-taught the concept, and demonstrates proficiency the second time. In effect, the student has overcome a hurdle. Because of the extra time and focus the student was able to dedicate to the concept, the student has now demonstrated proficiency in a concept or skill that previously seemed too difficult.

We view hurdles as particularly valuable learning opportunities, and it is important for teachers and parents to celebrate the student’s effort and accomplishments. Part of the 2 Sigma approach involves teaching students grit and comfort with failure on the road toward mastery. We want students to view getting stuck as a motivation to work hard to overcome an obstacle, rather than leading to discouragement or self-doubt. Ultimately the student overcame this hurdle and was able to pass the lesson, which should provide encouragement for the next time there is a hurdle!

What is "Struggling?"

Sometimes, a student is still unable to demonstrate proficiency even after the second time going through the lesson. When this happens, iReady moves the student on to other skills in order to avoid excessive frustration. Meanwhile, the teacher is alerted to the fact that this student struggled and was unable to demonstrate proficiency with this particular lesson. The teacher will then check in with the student, and will decide whether or not to review the concept in question and/or assign an appropriate lesson for the student to do next in lieu of this additional information. The teacher may also choose to contact the student’s parents to discuss next steps if needed.

Back to Top

Still have more questions? Feel free to reach out at