Math Hack #2

The faster we can think, the faster we can absorb new material and the faster we can write exams.

It also allows us to do a sanity check that the calculations we’ve been doing are in the right ball park. 

Is there any quick way of calculating 74 × 76?

For today’s post, we’ll be considering two-digit numbers where the first digits are the same and the last digits add to 10. Multiply the first digit by the next higher digit, then attach the product of the last digits in the original two numbers. Example: 74 × 76 is 7 × 8 = 56 and 4 × 6 = 24; answer: 5624

Try the following:

83 x 87

54 x 56

32 x 38

In the days and weeks ahead you may notice how you can impress those around you—try comparing speeds of how fast you are compared to them.