Question

How do you find the fractional notation for the ratio of 490 to 413?

Answer 1

`490/413 = 70/59`

Explanation:

The ratio `490 : 413` can be written as a fraction: `490/413`

But fractions (and ratios) should always be in the simplest form.

`490/413`

Find a common factor... But how can we do this?

By inspection, factors of `490` include the following.
(There may be others)

`1,2,5,7,10,14,35,49,70,490`

Of these, the following are definitely NOT factors of `413`:
`2,5,10,14,35,70,490`

Check whether `7` is a factor `413 div7 = 59`
`59` is a prime number, so that's it!

`490/413 (div7)/(div7) =70/59`