Free Number Bonds Worksheets: Printable Practice for KS1

Number bonds are one of the most important concepts in early primary mathematics. A number bond is simply a pair of numbers that add together to make a given total — for example, 3 + 7 = 10 is a number bond to 10. Automatic recall of number bonds is the foundation for mental addition and subtraction, and children who know their number bonds fluently find all subsequent maths significantly easier. This guide explains what number bonds are, why they matter, and how worksheets can be used to build this essential knowledge.

**What Are Number Bonds?**

Number bonds (also called number pairs or addition facts) describe all the ways a number can be split into two parts. For the number 10, the number bonds are: 0 + 10, 1 + 9, 2 + 8, 3 + 7, 4 + 6, 5 + 5, 6 + 4, 7 + 3, 8 + 2, 9 + 1, 10 + 0.

Understanding number bonds at a deep level means a child can: — Add two numbers quickly without counting on fingers — Subtract by finding the missing part (if 3 + ? = 10, then 10 − 3 = 7) — Carry out mental addition of two-digit numbers (e.g., 34 + 16 = 50, because 4 + 6 = 10) — Understand the commutativity of addition (3 + 7 = 7 + 3) — Begin to understand the relationship between addition and subtraction

In the UK National Curriculum, children are expected to know number bonds to 10 by the end of Year 1 and number bonds to 20 by the end of Year 2. However, many children benefit from beginning with number bonds to 5 in Reception and early Year 1.

**Number Bonds to 5**

Number bonds to 5 are the starting point for the youngest learners. The pairs are: 0+5, 1+4, 2+3, 3+2, 4+1, 5+0. These can be represented visually using five frames, cubes, fingers, or simple pictures. Worksheets at this level should use visual representations alongside the numerical equations to help children see what the abstract symbols mean.

Effective number bonds to 5 worksheets include: filling in the missing number in a part-whole model, completing a five-frame to show a given number bond, drawing objects to match an addition sentence, and matching number bond pairs.

**Number Bonds to 10**

Number bonds to 10 are the most important set of number bonds for early maths. When children know 1+9, 2+8, 3+7, 4+6, 5+5 (and their reverses) automatically, they can add any single-digit numbers mentally by bridging through 10. For example, 7 + 5 becomes: 7 + 3 (to make 10) + 2 = 12.

Worksheets for number bonds to 10 should progress through different representations and question types. Begin with ten-frame worksheets where children colour or draw objects to show the two parts of 10. Move on to number bond trees and part-whole models where children fill in missing numbers. Include both "3 + __ = 10" (missing addend) and "10 − 3 = __" (subtraction) to make the inverse relationship explicit.

Speed challenge worksheets — where children complete as many number bonds to 10 as possible in one minute — are excellent for building automaticity once the concepts are understood. Seeing their own time improve session after session is highly motivating for children.

**Number Bonds to 20**

Once number bonds to 10 are secure, children can use them to derive number bonds to 20. If they know 4 + 6 = 10, they can quickly work out 14 + 6 = 20 and 4 + 16 = 20. This extension of existing knowledge, rather than learning a completely new set of facts, is a powerful mathematical strategy.

Number bonds to 20 worksheets should make this connection explicit. Paired worksheets that show 4 + 6 = 10 alongside 14 + 6 = 20 and ask children to explain the pattern help develop mathematical reasoning as well as fact recall.

Other useful number bonds to 20 activities include: number bond dominoes (matching a number to its pair to make 20), missing number problems in addition and subtraction sentences, and word problems that require children to identify which number bond to apply.

**Beyond 20: Number Bonds to 100**

In Year 2 and Year 3, children begin working with number bonds to 100 — understanding that pairs of multiples of 10 add to 100 (30 + 70, 40 + 60) and later that any pair of two-digit numbers might bond to 100 (35 + 65, 48 + 52). These are an essential foundation for mental calculation strategies and should be introduced through worksheets that link back to the number bonds to 10 that children already know.

**Using Part-Whole Models**

Part-whole models (also called bar models or cherry diagrams) are a highly effective visual representation for number bonds. A circle at the top represents the whole, with two circles below representing the two parts. Children complete the model by filling in the missing whole or missing part.

Part-whole model worksheets are extremely flexible — the same format works for number bonds to 5, 10, 20, or 100, and for any number the teacher wishes to focus on. They also naturally link to subtraction, making the inverse relationship between addition and subtraction visually clear.

**Practical Games and Activities for Number Bonds**

Worksheets are most effective when combined with practical activities. Number bond snap (matching pairs of cards that add to the target number), number bond hopscotch (children call out the missing partner as they jump), and simple dice games where children roll two dice and decide if they make the target number all reinforce the same knowledge in different modalities.

**Generate Free Number Bonds Worksheets Instantly**

Worksheets Generator creates free, customised number bonds worksheets for any target number and age group. Select the appropriate age (Reception for bonds to 5, Year 1 for bonds to 10, Year 2 for bonds to 20), type the topic — "number bonds to 10", "number bonds to 20 part-whole model", "missing number bonds to 5", or "number bonds to 100" — choose Beginner or Intermediate difficulty, and click Create. Each worksheet is unique, includes a full answer key, and is ready to print immediately.