True or False? Number Sentences and Gaps

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What this lesson covers

  • × means groups of, and ÷ means share into equal groups.
  • The = sign means both sides are the same amount.
  • > means greater than and < means less than.
  • Work out one side to find the number in the gap.
Key idea

The signs

  • Each sign tells you what to do with the numbers.
SignMeansExample
+add4 + 2 = 6
−take away6 − 2 = 4
×groups of3 × 2 = 6
÷share equally6 ÷ 2 = 3
=is the same as6 = 6
Key idea

Greater than and less than

  • > means is greater than. < means is less than.
  • 16 > 60 says 16 is greater than 60. That is false.
  • Check each sentence by comparing tens first.
SentenceTrue or false?
16 > 60false
75 < 105true
99 > 98true
110 < 101false
Key idea

Equals means the same as

  • Work out both sides. If they match, the sentence is true.
  • 2 + 2 + 2 = 3 × 2: the left side is 6 and the right side is 6. True.
SentenceLeft sideRight sideTrue or false?
2 + 2 + 2 = 3 × 266true
5 + 4 = 10 − 199true
7 + 3 = 3 × 3109false
Worked example

Fill the gap

  • 18 + ? = 17 + 6. The right side is 23. 18 and what make 23? 5.
  • Or notice that 18 is one more than 17, so the gap is one less than 6.
  • 6 ÷ ? = 2. Put 6 counters into groups of 2. You make 3 groups, so it is 3.
SentenceMissing number
18 + ? = 17 + 65
6 ÷ ? = 23
4 × ? = 205
? − 7 = 1017
Key idea

Try it: make both sides the same

Worked example

Use a number line or ten frames

  • 9 + ? = 15. Start at 9 on a number line and hop to 15. That is 6 hops.
  • Or fill a ten frame: 9 counters, 1 more makes 10, then 5 more makes 15. 1 and 5 is 6.
Key idea

Try it: hop to fill the gap

Common mistakes

  • In 18 + ? = 17 + 6, the missing number is 23.
    23 is the total on the right side. The gap needs 5, so 18 + 5 also makes 23.
  • 16 > 60 is true.
    Read > as is greater than. 16 is not greater than 60, so it is false.
  • 2 + 2 + 2 = 3 × 2 is false, because the signs are different.
    Work out each side. Both are 6, so it is true.

Your turn

1

True or false: 45 > 54?

2

True or false: 5 + 5 = 2 × 5?

3

8 ÷ ? = 4. What is the missing number?

4

9 + ? = 8 + 4. What is the missing number?

5

? × 10 = 70. What is the missing number?

Show answer

1. false 2. true 3. 2 4. 3 5. 7

Summary

What to take away

  • × is groups of; ÷ is share equally.
  • = means both sides are the same amount.
  • > is greater than; < is less than.
  • Work out the full side first, then fill the gap.
Report a mistake

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