4 number facts + - know 1 fact know 4. 16 + 4 = 20 16 20 4 each number sentence can be written in...
Post on 21-Jan-2016
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4 number facts + -
Know 1 fact know 4
16 + 4 = 20
16
20
4
Each number sentence can be written in four ways.
Learn one, know four
+
=4 + 16 = 20
16
20
4
+
=20 – 4 = 16
16
20
4
=
–20 – 16 = 4
16
20
4
=
–
20 – 8 = 12
20 – 12 = 8
12 + 8 = 20
8 + 12 = 20 14 + 6 = 20
6 + 14 = 20
20 – 6 = 14
20 – 14 = 6
Learn one, know four
20 – 8 = 12
20 – 12 = 8
12 + 8 = 20
8 + 12 = 20 14 + 6 = 20
6 + 14 = 20
20 – 14 = 6
Can you fill in the gaps?
20 – 6 = 14
Learn one, know four
9 + 7 = 16
When you learn one number fact, you are really learning four.
If we learn…
9 + 5 = 14
Learn one, know four
What is the missing figurein these?
Then we also know…
5 + 9 = 1414 – 9 = 514 – 5 = 9
7 + 9 = 16
16 – 7 = 9
16 – 9 = 7
7 + 9 = 16
9 + 7 = 16
16 – 7 = 9
16 – 9 = 7
Learn one, know four
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