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Step-by-step practice: Maths · Level 1Chapter 4 · Number bonds to 5
Step-by-step Maths Level 1 · Number bonds to 5 · Lesson 4.4

Step-by-step Maths Level 1: Missing numbers in sums

Part of the Step-by-step Maths Level 1 number bonds to 5 chapter. Chapter overview · whole chapter on one page

4.4

Missing numbers in sums

Level 1
Find the missing number in a sum that makes 5

A sum has a box where the missing number goes.

Ask: “What do I add to this number to make 5?”

Key ideas

  • The box is the missing number.
  • A sum with a box still has the answer 5.
  • Use your bonds to 5 to find the box.
Worked example 4.4.1
Fill in the box: 4 + □ = 5

Method. Find the missing part. Ask what goes with the known part to make the whole.

  1. Look at the whole and the part you know. The whole is 5 and the known part is 4.
    5 and 4
  2. Count on from the known part to the whole. Or take the known part away from the whole.
    5 - 4 = 1
  3. Write the missing part.
    1

Check. Put the two parts back together: 4 and 1 make 5.

Watch out. The two parts always add up to the whole.

Worked example 4.4.2
Fill in the box: □ + 2 = 5

Method. Find the missing part. Ask what goes with the known part to make the whole.

  1. Look at the whole and the part you know. The whole is 5 and the known part is 2.
    5 and 2
  2. Count on from the known part to the whole. Or take the known part away from the whole.
    5 - 2 = 3
  3. Write the missing part.
    3

Check. Put the two parts back together: 2 and 3 make 5.

Watch out. The two parts always add up to the whole.

Worked example 4.4.3
Fill in the box: 0 + □ = 5

Method. Find the missing part. Ask what goes with the known part to make the whole.

  1. Look at the whole and the part you know. The whole is 5 and the known part is 0.
    5 and 0
  2. Count on from the known part to the whole. Or take the known part away from the whole.
    5 - 0 = 5
  3. Write the missing part.
    5

Check. Put the two parts back together: 0 and 5 make 5.

Watch out. The two parts always add up to the whole.

Watch out

Watch out. The box can be on either side of the plus sign. The answer is still the missing part.

Exam tip

Grown-up tip. Let your child use fingers to check. Hold up 5 fingers, put some down, and count the fingers still up.

Exercise 4D  Missing numbers in sums

Non-calculator
1
FFill in the box: 3 + □ = 5
2
FFill in the box: □ + 1 = 5
3
FFill in the box: 0 + □ = 5
4
FFill in the box: □ + 5 = 5
5
FFill in the box: 2 + □ = 5
6
FFill in the box: □ + 4 = 5
7
FFill in the box: 5 + □ = 5
8
FFill in the box: □ + 5 = 5
9
FFill in the box: 5 + □ = 5
10
FFill in the box: □ + 5 = 5
11
FFill in the box: 5 + □ = 5
12
FFill in the box: □ + 4 = 5
13
FFill in the box: 3 + □ = 5
14
FFill in the box: □ + 1 = 5
15
PSFill in the box: 2 + □ = 5
16
RFill in the box: □ + 0 = 5

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