Question

Draw or write to show two ways to use a doubles fact to find 6+7.

Answer 1

Doublets means when two same single digit number or two digit number are added, we get the result equal to number multiplied by 2.For Example

1+1=1×2=2

2+2=2×2=4

...............

..................

9+9=2×9=18

Now, we have to find sum Using doublets.

First Way

→6+7

=6+6+1

=2×6+1

=12+1

=13

Second way

→6+7

→7-1+7

→7+7-1

→2×7-1

→14-1

=13

Answer 2

Doubles fact is adding two addends that are the same.
1 + 1 = 2
2 + 2 = 4
3 + 3 = 9
4 + 4 = 8
5 + 5 = 10
6 + 6 = 12
7 + 7 = 14
8 + 8 = 16
9 + 9 = 18
10 + 10 = 20

Except 3 + 3; all sums are even numbers.

Doubles + 1 fact:

6 + 6 = 12
12 + 1 = 13
6 + 7 = 13

This is better explained using tokens or counters.