Question

What different ways are there of finding `48 -: 8` ?

Answer 1

A few thoughts...

Explanation:

Here are a few ideas:

• If you know that `6 xx 8 = 48` then it follows that `48 -: 8 = 6`

• If you know that `7^2 = 49` then note that `48 = 49-1 = 7^2-1^2 = (7-1)(7+1) = 6 xx 8`

• Notice that `48 = 40+8 = (10xx4)+8 = (10xx1/2xx8)+8 = (5xx8)+(1xx8) = (5+1)xx8 = 6xx8`

• Add `8`'s until you get `48` and count the number of `8`'s you had to use: `48=overbrace(8+8+8+8+8+8)^(6 xx 8)`

• The other way round, we could count the number of times we need to subtract `8` from `48` until we get to `0`: `48 rarr 40 rarr 32 rarr 24 rarr 16 rarr 8 rarr 0`. That was `6` times.

Answer 2

I have one thought to add to George's excellent answer.

Explanation:

`48 -: 8` can also be written `48/8`

And I can reduce the fraction because both numbers are even:

`48/8 = (2 xx 24)/(2 xx 4) = 24/4`

If I notice that `24/4 = 6`, then I can finish. If not, then I see that the numbers are both even, so I can reduce again:

`48/8 = 24/4 = 12/2`.

And finish with `6`.