Multiplying Lower Numbers 61
25 – 1 = 24
+1
5 6 × 4 = 5
–1
25 – 1 = 24 Answer
Th is is a long and complicated method for multiplying low numbers,
but it shows we can make the method work with a little ingenuity.
Actually, these strategies will develop your ability to think laterally,
which is very important for mathematicians, and also for succeeding
in life.
Let’s try some more, even though you probably know your lower
times tables quite well:
5 4 × 4 =
–1
–1
Subtract crossways:
4 – 1 = 3
Multiply your answer by the reference number:
3 × 10 = 30
Th irty divided by 2 equals 15. Now multiply the numbers in the
circles:
1 × 1 = 1
Add that to our subtotal:
brent
(Brent)
#1