To find an equivalent fraction, you need to do the same thing to both the numerator and the denominator.

An easy one here would be to divide both by 10, or remove the zeros. That will change 10/20 to 1/2, which is one equivalent fraction.

You can also multiply both the numerator and denominator. For example, you could multiply both by 2, and that will give you your second equivalent fraction of 20/40.