New
New
Year 2

Find the missing part when subtracting two-digit numbers

I can solve missing number equations involving subtracting two-digit numbers.

New
New
Year 2

Find the missing part when subtracting two-digit numbers

I can solve missing number equations involving subtracting two-digit numbers.

Lesson details

Key learning points

  1. The parts and the whole can be rearranged to help us solve equations.
  2. A bar model or a part-part-whole model can be used to help understand missing number equations.
  3. Addition can be used to check subtraction equations.
  4. Addition can be used to solve missing number subtraction equations.

Common misconception

When presented with missing number equations with larger numbers, children may not automatically make the link to the part-part-whole structure.

Use visual representations to consolidate understanding and to encourage children to manipulate the numbers or equations involved so they can utilise what they already know.

Keywords

  • Part - A piece or section of a whole.

  • Whole - All of something; complete.

This lesson involves building upon prior knowledge to deepen understanding of the structure of subtraction equations. Children are encouraged to manipulate individual numbers in equations in order to encourage confidence and mentally flexibility.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which of the following equations will result in a multiple of 10?
56 − 65 = ?
Correct answer: 56 − 36 = ?
56 − 53 = ?
Q2.
Which number line could be used to solve the equation shown? 73 − 36 = ?
A
B
Correct answer: C
Q3.
Use the pattern to predict the answer to the next equation.
An image in a quiz
Correct Answer: 13
Q4.
Use the pattern to predict the next equation in the sequence. The next equation will be
An image in a quiz
Correct Answer: 74 − 56 = 18
Q5.
Write a subtraction equation, then solve it to find the missing part in the bar model.
An image in a quiz
Correct Answer: 93 − 59 = 34, 93 − 50 − 9 = 34
Q6.
Match each equation to the number that correctly completes it.
Correct Answer:64 − 27 = ?,37

37

Correct Answer:91 − 48 = ?,43

43

Correct Answer:83 − 26 = ?,57

57

6 Questions

Q1.
Which equation has a whole that is a multiple of 10
{{ }} − 23 = 85
Correct answer: {{ }} − 42 = 28
{{ }} − 28 = 37
Q2.
Which bar model represents the equation shown? 43 = 60 − ?
Correct answer: A
B
C
Q3.
Write the addition equation you would use to check this subtraction. 57 − 33 = 24
Correct Answer: 24 + 33 = 57
Q4.
Which number would solve the equation. 76 − = 23
Correct answer: 53
99
32
Q5.
Which bar model would represents the equation shown? − 42 = 25
A
Correct answer: B
C
Q6.
Solve the equation − 42 = 29
Correct Answer: 71