Easy way for multiplying numbers close to 100.

Suppose you want to multiply 88 by 98.

 
Not easy,you might think. But with
VERTICALLY AND CROSSWISE
you can give the answer immediately,
using the same method as above
 
Both 88 and 98 are close to 100.
88 is 12 below 100 and 98 is 2 below 100.
You can imagine the sum set out like this:

As before the 86 comes from subtracting crosswise:
88 - 2 = 86 (or 98 - 12 = 86: you can subtract either way,
you will always get the same answer).
 
And the 24 in the answer is just 12 x 2: you
multiply vertically.
So 88 x 98 = 8624

This is so easy it is just mental arithmetic.
 
Try some:
1)  87 x 98 =
 
2)  88 x 97 =
 
3)  77 x 98 =
 
4)  93 x 96 =
 
5)  94 x 92 =