52 Speed Math for Kids
We divide by 2 to get 3,000. We then multiply the numbers in the
circles and add the result to 3,000:
3 × 7 = 21
3,000 + 21 = 3,021
Our problem will end up looking like this:
+3
+7
50 53 × 57 = 6,000
3,000
- 21
3,021 Answer
Let’s try one more:
+1
+14
50 51 × 64 =
Add diagonally and multiply the result by the reference number
(multiply by 100 and then divide by 2):
64 + 1 = 65
65 × 100 = 6,500
Th en we halve the answer.
Half of 6,000 is 3,000. Half of 500 is 250. Our subtotal is 3,250.
Now multiply the numbers in the circles:
1 × 14 = 14
Add 14 to the subtotal to get 3,264.