164 Speed Math for Kids
39
+1
8
40 31.-1 9
Four times 8 is 32, with –1 remainder, which we carry as –10, and
we ignore the 9 for the moment. We multiply 8 times +1 to get +8,
which we add to the next digit, 9, to get 17, then we minus the 10
carried to get a remainder of 7.
39
+1
8 r7
40 31.-1 9
With practice, this concept will become easy.
Test you rself
Try these problems for yourself. Calculate to one decimal
place.
a) 224 ÷ 29 =
b) 224 ÷ 41 =
Let’s calculate the answers together.
29
+1
- 72
30 22.^140
We have divided both numbers by 10. Three divides into
22 seven times (3 × 7 = 21) with 1 remainder, which we
carry to the next digit, 4, to make 14. We multiply 7 × 1 =
7, and add to the 14 to get 21.
Now divide 21 by 3 to get 7, with no remainder to carry.
Multiply the last digit of the answer, 7, by 1 to get 7, which