Question

What is 126 over 399 as a ratio

Answer 1

126:399 is one of the ratios to use and 42:133.

Answer 2

$\frac{126}{399} = \frac{42}{133}$  which can also be expressed as 42:133 or 42 to 133.

I knew I could divided each number by 3 because the sum of the digits 1+2+6  or 3 + 9 + 9 sums to a multiple of 3 or if you add the sums to a single digit you will get 3, 6 or 9
1+ 2+ 6 = 9
3 + 9 + 9 = 15 and 1+ 5 = 6