New
New
Year 2

Explain what happens when you add and subtract ten to a multiple of ten

I can explain what happens when you add and subtract ten to a multiple of ten.

New
New
Year 2

Explain what happens when you add and subtract ten to a multiple of ten

I can explain what happens when you add and subtract ten to a multiple of ten.

Lesson details

Key learning points

  1. Ten can be added to or subtracted from a multiple of ten.
  2. When you add ten to a multiple of ten the tens number increases by one
  3. When you subtract ten from a multiple of ten the tens number decreases by one
  4. If 3 + 1 is equal to 4 then 3 tens + 1 ten is equal to 4 tens which is equal to 40

Common misconception

Children may not see the link between adding ones and adding tens. They may add or subtract one instead of ten or muddle addition and subtraction, so may subtract ten instead of add ten to a number.

Reinforce understanding of unitising by describing each group of objects in ones or tens, e.g. five cubes plus 1 cube, 5 tens plus 1 ten and talk through what is happening. Show this with equipment in tens and ones such as straws or cubes.

Keywords

  • Increase - Make something bigger (in size or quantity).

  • Decrease - Make something smaller (in size or quantity).

  • Multiple - A multiple is the result of multiplying a number by another whole number.

Being able to unitise is fundamental in understanding place value, it allows children to move from additive to multiplicative thinking which will be needed for future work on multiplication and division. When counting and grouping objects, reinforce unitising language e.g. this is 3 groups of ten.
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.
What number comes next in the counting sequence? 30, 40, 50,
30
40
50
Correct answer: 60
Q2.
What number is missing in the counting sequence? 50, 60, , 80, 90
50
60
Correct answer: 70
80
90
Q3.
What number comes next in the backwards counting sequence? 30, 20,
Correct answer: 10
20
30
40
Q4.
What multiple of 10 is the arrow pointing to on this number line?
An image in a quiz
10
20
Correct answer: 30
40
50
Q5.
Which arrow shows the position of 90 on this number line?
An image in a quiz
a
b
Correct answer: c
Q6.
What is a good estimate for this multiple of 10 shown on the number line?
An image in a quiz
0
Correct answer: 10
30
30

6 Questions

Q1.
What is the missing number?
An image in a quiz
30
Correct answer: 40
50
Q2.
Ten more than 50 is
40
50
Correct answer: 60
Q3.
Ten more than 40 is 50, so ten less than 50 is
30
Correct answer: 40
50
Q4.
Match the equation to the correct multiple of 10
Correct Answer:40 + 10 =,50

50

Correct Answer:80 - 10 =,70

70

Correct Answer:70 + 10 =,80

80

Correct Answer:20 - 10 =,10

10

Q5.
Ten less than 70 is
Correct answer: 60
80
70
Q6.
Match the pairs of equations to complete the sentence. I know that so
Correct Answer:3 + 1 = 4 ,30 + 10 = 40

30 + 10 = 40

Correct Answer:1 + 5 = 6,10 + 50 = 60

10 + 50 = 60

Correct Answer:4 + 1 = 5,40 + 10 = 50

40 + 10 = 50

Correct Answer:6 + 1 = 7,60 + 10 = 70

60 + 10 = 70

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