Use efficient methods to solve subtraction equations | Maths

Starter quiz

In which of the following equations will you have to bridge 10?

65 − 26 = ? ✓

38 − 27 = ?

61 − 60 = ?
Which of the following equations is correct?

83 − 26 = 57 ✓

45 − 28 = 13

94 − 68 = 34
Solve the following equation. 43 − 25 = ______

'18' ✓
Andeep has 76 tickets. He buys the ball. How many tickets does he have left?

'47' ✓
Andeep had 66 tickets. He bought a plane and now he has 23 tickets left. How much did the plane cost?

'43' ✓
Match each equation to the correct answer.

47 − 28 = ___

⇔

19 ✓

86 − ___ = 34

⇔

52 ✓

76 − 28 = ___

⇔

48 ✓

Exit quiz

Write a subtraction equation to calculate the missing part in this bar model and solve it.

'50 − 1 = 49' ✓
Which of the following equations will have a difference of 1?

83 − 73 = ?

22 − 21 = ? ✓

38 − 28 = ?
One of the missing numbers in this equation is 57 Which of the following could be the other missing number? ___ − ___ = 1

56 ✓

67

58 ✓
In which of the following equations will the missing part be a multiple of 10?

93 − 73 = ? ✓

22 − 21 = ?

38 − 37 = ?
Solve the equation. 88 − 58 = ______

'30' ✓
What is the missing digit in the equation?

'2' ✓

Worksheet

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Lesson Details

Key learning points

Consecutive numbers always have a difference of 1
If the whole and the known part in a subtraction equation are consecutive numbers, the missing part will always be 1
If the known part in a subtraction equation is 1, the whole and the missing part will be consecutive numbers
When the ones digits in the whole and the known part are the same, the missing part will be a multiple of 10

Common misconception

When writing equations with consecutive numbers, children may write in the order they are counted , e.g. 56-57 = forwards

Give missing number equations and represent them on part-part-whole models and bar models to consolidate understanding of which numbers in the equation represent the whole and the parts.

Keywords

Consecutive - Numbers which follow each other in order, without gaps.
Difference - The result of subtracting one number from another.
Whole - All of something; complete.
Part - A piece or section of a whole.