Multiplication Using Any Reference Number 55
44,800 + 144 = 44,944
+12
+12
200 212 × 212 = 224
44,800
- 144
44,944 Answer
Let’s try another. How about multiplying 511 by 503? We use 500
as a reference number.
+11
+3
500 511 × 503 =
Add crossways.
511 + 3 = 514
Multiply by 500. (Multiply by 1,000 and divide by 2.)
514 × 1,000 = 514,000
Half of 514,000 is 257,000. (How did we work this out? Half of
500 is 250 and half of 14 is 7.)
Multiply the numbers in the circles, and add the result to our
subtotal.
3 × 11 = 33
257,000 + 33 = 257,033