This trick is used for multiplying numbers where the first digits are the same and the last digits add up to 10.

Let’s learn to multiply fast.

Have fun with the trick

32 x 38 = 1216
Both numbers here start with 3 and the last
digits ( 2 and 8 ) add up to 10.

So we just multiply 3 and 4 (first digit + 1)
to get 12 for the first part of the answer.

And we multiply the last digits: 2 x 8 = 16 to
get the last part of the answer.

Let’s try another one

45 x 45 = 2025

Both numbers here start with 4 and the last
digits (5 + 5) add up to 10.

So we just multiply 4 and 5 (first digit + 1)
to get 20 for the first part of the answer.

And we multiply the last digits: 5 x 5 = 25 to get the last
part of the answer.

Little Variation

31 x 39 = 1209

Both numbers here start with 3 and the last digits (1 and 9) add up to 10.

So we just multiply 3 and 4 (first digit + 1) to get 12 for the first part of the answer.

And we multiply the last digits: 9 x 1 = 09 to get the last part of the answer. Here we write 09 as the answer, as the last part should be a double digit numbers.

Time for you to try

93 x 97 =
39 x 31 =
16 x 14 =
82 x 88 =
94 x 96 =
71 x 79 =
65 x 65 =
59 x 51 =
22 x 28 =