Kiss those Math Headaches GOODBYE!

Posts tagged ‘Teen Numbers’

Multiplication Trick #4: Multiplying Teen Numbers


Ever wondered if there’s a quick way to multiply two number in the teens, problems like: 14 x 17, or 18 x 16?

Well, there is. And if you just stick around for two minutes, you’ll learn the trick. Let’s start wih 18 x 16.

First, add up the two digits in the one’s place. Here that’s the 8 and the 6. 8 + 6 = 14.

Next take that sum (14) and add 10 to it. 14 + 10 = 24.

Then tack a zero on at the end. 24 becomes 240.

Finally multiply the two numbers in the one’s place, and add the sum to the 240.

8 x 6 = 48, and 240 + 48 = 288.

That’s your answer. This may seem tricky at first, but it gets pretty easy if you try it a few times. Trust me …

O.K., don’t trust me. But just try it one more time, with 14 x 17, and see for yourself.

4 + 7 = 11. 11 + 10 = 21.

21 becomes 210.

4 x 7 = 28, and 210 + 28 = 238.

That’s all there is to it.

Now try these:

a) 13 x 16
b) 12 x 17
c) 14 x 19
d) 12 x 19
e) 13 x 14
f) 17 x 18
g) 19 x 17
h) 15 x 19
j) 16 x 17
k) 18 x 19

Answers:

a) 13 x 16 = 208
b) 12 x 17 = 204
c) 14 x 19 = 266
d) 12 x 19 = 228
e) 13 x 14 = 182
f) 17 x 18 = 306
g) 19 x 17 = 323
h) 15 x 19 = 285
j) 16 x 17 = 272
k) 18 x 19 = 342

Advertisements