Grade K · Operations & Algebraic Thinking

Number Pairs Within 5

Break a number into two parts in more than one way.

Curriculum placementK.OA.A.315 minute lesson
Structured mathInteractive visual20 practice questionsNo account required
Learning goalDecompose numbers through 5 into pairs and record the parts with an equation.
Why it mattersBreaking numbers apart is one of the most important mental-math strategies for addition, subtraction, fractions, and algebra.
01Lesson step

A whole can be split different ways

Five can be made from 0 and 5, 1 and 4, 2 and 3, and the reversed pairs. The whole stays five even when the parts change.

02Lesson step

Record the relationship

A number bond can be written as an equation such as 5 = 2 + 3.

Key terms

Words to know

Compose
Put parts together to make a whole.
Decompose
Break a whole into parts.
Number bond
A picture showing how parts combine to make a whole.
Equation
A statement showing that two mathematical expressions are equal.

Interactive math lab · 🧱 blocks

Change it. See it. Understand it.

Split the blocks into two groups. The whole stays 5.

Live model
5
2
3

5 = 2 + 3

What the visual is showing
Whole5
Part A2
Part B3

Worked examples

See the idea in action.

Split 55 = 2 + 3

Two and three are parts that combine to make five.

Another split5 = 1 + 4

The same whole can be decomposed a different way.

Guided practice

Work through 20 questions, one step at a time.

Choose an answer, check your reasoning, then move forward. Your score updates as you go.

Score0/200 checked
Question 1 of 200% complete
Question 01Choose one answer

What number is one more than 1?

Use the lesson above if you need a hint.

Curriculum reference

Built as a continuous K–12 progression.

The sequence follows widely used K–12 mathematics progressions and references the Common Core mathematics framework. Explanations, examples, interactive models, and practice questions are original FreeLearnHub material.

View mathematics standards ↗