Page 40 - PlayFacto_A1
P. 40
Make 10 and add
Add three numbers by composing two numbers that make the sum of 10.
: Add two numbers that make the sum of 10 first.
7+3+4 5+4+6 5+3+5
10 + 4 = 14 5 + 10 = 15 10 + 3 = 13
Add numbers by decomposing a number into two numbers.
: Decompose a number that is less than the other into two numbers and make
the sum of 10.
3+9 8+5
2+1+9 8+2+3
2 + 10 = 12 10 + 3 = 13
Example 1 Fill in the blanks. ⑵ 4+7+3
⑴ 2+8+3 4+ =
+3=
⑶ 6+5 ⑷ 5+9
6+ +1 4+ +9
10 + 1 = + 10 =
4. Making 5 and 15 37
Add three numbers by composing two numbers that make the sum of 10.
: Add two numbers that make the sum of 10 first.
7+3+4 5+4+6 5+3+5
10 + 4 = 14 5 + 10 = 15 10 + 3 = 13
Add numbers by decomposing a number into two numbers.
: Decompose a number that is less than the other into two numbers and make
the sum of 10.
3+9 8+5
2+1+9 8+2+3
2 + 10 = 12 10 + 3 = 13
Example 1 Fill in the blanks. ⑵ 4+7+3
⑴ 2+8+3 4+ =
+3=
⑶ 6+5 ⑷ 5+9
6+ +1 4+ +9
10 + 1 = + 10 =
4. Making 5 and 15 37
