Common Core Math Standards: A Parent-Friendly Guide (K–3)
Understand the Common Core State Standards for math in plain language. Know exactly what your child should learn at each grade level, from counting to multiplication.
What Are Common Core Math Standards?
The Common Core State Standards (CCSS) define what students should know and be able to do at each grade level in math and English language arts. They were developed by educators and experts across 41 states to ensure consistent, high-quality learning goals nationwide.
For homeschool parents, CCSS provides a clear, grade-by-grade roadmap — even if your state doesn't require you to follow it. Knowing these benchmarks helps you identify gaps, choose curriculum, and ensure your child is on track for their grade level.
Below are the key math standards for grades K through 3, written in plain language with the official standard codes for reference.
Kindergarten: Counting & Cardinality (K.CC)
The foundation of all math starts here. Kindergarteners learn to count, compare numbers, and understand that numbers represent quantities.
✓K.CC.A.1 — Count to 100 by ones and by tens.
✓K.CC.A.2 — Count forward beginning from a given number (not always starting at 1).
✓K.CC.A.3 — Write numbers from 0 to 20. Represent a number of objects with a written numeral.
✓K.CC.B.4 — Understand the relationship between numbers and quantities; connect counting to cardinality (the last number counted tells "how many").
✓K.CC.B.5 — Count to answer "how many?" questions about as many as 20 things arranged in a line, array, or circle.
✓K.CC.C.6 — Identify whether the number of objects in one group is greater than, less than, or equal to the number in another group.
✓K.CC.C.7 — Compare two numbers between 1 and 10 presented as written numerals.
Kindergarteners begin to understand what addition and subtraction mean through hands-on activities with small numbers.
✓K.OA.A.1 — Represent addition and subtraction with objects, fingers, mental images, drawings, sounds, acting out situations, or equations.
✓K.OA.A.2 — Solve addition and subtraction word problems, and add and subtract within 10.
✓K.OA.A.3 — Decompose numbers less than or equal to 10 into pairs in more than one way (e.g., 5 = 2 + 3 and 5 = 4 + 1).
✓K.OA.A.4 — For any number from 1 to 9, find the number that makes 10 when added to the given number.
✓K.OA.A.5 — Fluently add and subtract within 5.
Grade 1: Operations & Algebraic Thinking (1.OA)
First graders build fluency with addition and subtraction within 20 and begin solving word problems with unknowns in different positions.
✓1.OA.A.1 — Use addition and subtraction within 20 to solve word problems involving adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions.
✓1.OA.A.2 — Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20.
✓1.OA.B.3 — Apply properties of operations as strategies to add and subtract (commutative and associative properties).
✓1.OA.C.5 — Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).
✓1.OA.C.6 — Add and subtract within 20, demonstrating fluency within 10. Use strategies such as counting on, making ten, decomposing a number, and creating equivalent but easier sums.
✓1.OA.D.7 — Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false.
✓1.OA.D.8 — Determine the unknown whole number in an addition or subtraction equation relating three whole numbers.
Grade 1: Number & Operations in Base Ten (1.NBT)
First graders extend their understanding of place value and use it to add and subtract.
✓1.NBT.A.1 — Count to 120, starting at any number less than 120. Read and write numerals and represent a number of objects with a written numeral.
✓1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones.
✓1.NBT.B.3 — Compare two two-digit numbers based on meanings of the tens and ones digits, using >, =, and < symbols.
✓1.NBT.C.4 — Add within 100, including a two-digit number and a one-digit number. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones.
✓1.NBT.C.6 — Subtract multiples of 10 in the range 10–90 from multiples of 10 in the range 10–90.
Grade 1: Measurement & Data (1.MD)
First graders learn to measure lengths, tell time, and organize data.
✓1.MD.A.1 — Order three objects by length; compare the lengths of two objects indirectly by using a third object.
✓1.MD.A.2 — Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object end to end.
✓1.MD.B.3 — Tell and write time in hours and half-hours using analog and digital clocks.
✓1.MD.C.4 — Organize, represent, and interpret data with up to three categories.
Grade 2: Operations & Algebraic Thinking (2.OA)
Second graders master addition and subtraction within 100 and begin building the foundation for multiplication.
✓2.OA.A.1 — Use addition and subtraction within 100 to solve one- and two-step word problems.
✓2.OA.B.2 — Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.
✓2.OA.C.3 — Determine whether a group of objects (up to 20) has an odd or even number of members.
✓2.OA.C.4 — Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.
Grade 2: Number & Operations in Base Ten (2.NBT)
Second graders deepen place value understanding and build fluency with multi-digit addition and subtraction.
✓2.NBT.A.1 — Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones.
✓2.NBT.A.2 — Count within 1000; skip-count by 5s, 10s, and 100s.
✓2.NBT.A.3 — Read and write numbers to 1000 using base-ten numerals, number names, and expanded form.
✓2.NBT.A.4 — Compare two three-digit numbers using >, =, and < symbols.
✓2.NBT.B.5 — Fluently add and subtract within 100 using strategies based on place value, properties of operations, and the relationship between addition and subtraction.
✓2.NBT.B.7 — Add and subtract within 1000 using concrete models, drawings, and strategies based on place value.
✓2.NBT.B.8 — Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.
Grade 3: Operations & Algebraic Thinking (3.OA)
Third graders learn multiplication and division — the most important new operation they will encounter in elementary school.
✓3.OA.A.1 — Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each.
✓3.OA.A.2 — Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as the number of objects in each share when 56 objects are partitioned equally into 8 shares.
✓3.OA.A.3 — Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities.
✓3.OA.A.4 — Determine the unknown whole number in a multiplication or division equation relating three whole numbers.
✓3.OA.B.5 — Apply properties of operations as strategies to multiply and divide (commutative, associative, and distributive properties).
✓3.OA.B.6 — Understand division as an unknown-factor problem. For example, find 32 ÷ 8 by finding the number that makes 32 when multiplied by 8.
✓3.OA.C.7 — Fluently multiply and divide within 100. By the end of Grade 3, know from memory all products of two one-digit numbers.
Grade 3: Number & Operations — Fractions (3.NF)
Third grade is where fractions are formally introduced. Students learn to understand fractions as numbers on a number line.
✓3.NF.A.1 — Understand a fraction 1/b as the quantity formed by 1 part when a whole is partitioned into b equal parts; understand a fraction a/b as the quantity formed by a parts of size 1/b.
✓3.NF.A.2 — Understand a fraction as a number on the number line; represent fractions on a number line diagram.
✓3.NF.A.3 — Explain equivalence of fractions and compare fractions by reasoning about their size.
How to Use This Guide
You don't need to memorize these codes. Use this guide as a reference when choosing worksheets, planning lessons, or evaluating your child's progress. If a worksheet says "aligned to 1.OA.C.6," you can look it up here to understand exactly what skill it covers.
Remember: these are benchmarks, not rigid deadlines. Every child progresses at their own pace. If your first grader hasn't mastered all the 1.OA standards yet, that's perfectly normal — focus on building understanding, not rushing through checklists.
✓Use the standard codes to identify specific skills your child needs to practice.
✓Match worksheets to standards for targeted, efficient practice.
✓Review earlier grade standards if your child has gaps — it's never too late to fill them.
✓Pair this guide with our blog posts for strategies on teaching each skill.