New
New
Year 3

# Subtract 3-digit multiples of 10 by finding the difference between them

I can subtract 3-digit multiples of 10 by finding the difference between them.

New
New
Year 3

# Subtract 3-digit multiples of 10 by finding the difference between them

I can subtract 3-digit multiples of 10 by finding the difference between them.

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## Lesson details

### Key learning points

1. When numbers are close together, the difference between them is small.
2. Finding the difference means we count on from the subtrahend to the minuend.
3. A number line or a bar model can represent finding the difference.

### Common misconception

Children will often reverse the minuend and subtrahend because they don't always appear in the order that they would in an expression.

Give time to ensure that the children understand the bar model representation and encourage them to discuss which number is the minuend and which is the subtrahend before engaging in a strategy for mental subtraction.

### Keywords

• Minuend - The minuend is the number being subtracted from.

• Subtrahend - A subtrahend is a number subtracted from another.

• Difference - The difference is the result after subtracting one number from another.

### 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).

## Starter quiz

### 6 Questions

Q1.
Which of these subtraction expressions can be more efficiently solved by finding the difference?
Correct answer: 75 − 68 =
96 − 19 =
83 − 38 =
Q2.
What is the missing part in this bar model?
Correct Answer: 80, eighty, eight tens, 8 tens
Q3.
Match the numbers so that they make a pair with a sum of 100.

80

60

25

5

Q4.
Use a find the difference strategy to calculate: 54 − 47 =
Correct Answer: 7, seven, seven ones, 7 ones
Q5.
Use a partitioning strategy to find the sum of 135 and 270
Correct Answer: 405, four hundred and five
Q6.
Select all the multiples of 10
75
103

## Exit quiz

### 6 Questions

Q1.
Which of these is the correct equation represented by this bar model?
240 − 270 = ?
Correct answer: 270 − 240 = ?
270 + 240 = ?
240 + 270 = ?
Q2.
Which of these is the correct equation represented by this number line?
Correct answer: ? = 850 − 810
? = 850 + 810
? = 810 + 850
? = 810 − 850
Q3.
What is the difference between the two values shown in the bar model?
Q4.
What is the difference between the two values shown?
Correct Answer: 80, eighty, eight tens
Q5.
What is the difference between the two values shown?
Correct Answer: 90, ninety, nine tens, 9 tens
Q6.
Which of the pairs of numbers have the greatest difference?
270 and 290