Question

Explain how you can solve 8x8 if you know how to multiply with 4 but not how to multiply with 8

Answer 1

If you only know how to multiply with 4's, then you need to quickly convert the 8's to 4's.

We were given,


`8*8`

So we rewrite each of the 8's as


`(4*2)*(4*2)`

Perfectly for us,it turns out that the 2's will also give us a 4, so the whole thing becomes,


`4*4*2*2=4*4*4`


`\Rightarrow 8*8=4*4*4`

Now, let us multiply two of the 4's, to obtain,


`\Rightarrow 8*8=16*4`

Finally, let us multiply with the last 4 to get,


`\Rightarrow 8*8=64`