User:Muneeb.nagori/sandbox

Multiplying two 2 digit numbers between 11 and 19
To easily multiply 2 digit numbers together between 11 and 19 a simple algorithm is as follows (where a is the ones digit of the first number and b is the ones digit of the second number): (10+a)×(10+b) 100 + 10×(a+b) + a×b

which can be visualized as three parts to be added:

1 xx yy

for example:

17×16

1              = 100 13    (7+6)     = 10×(a+b) 42  (7×6)     = a×b 272  (total)