Who is asking: Parent
Compare the fractions
12/36 and ?/18.
The denominator of the fraction on the left is twice the denominator of the fraction on the right.
(36 = 218)
and hence the numerator on the left should be twice the numerator on the right. That is 12 should be twice the value of ?. Thus ? = 6.
12/36 and 4/?.
This time the numerator on the left is 3 times the numerator on the right so the denominators should be related by the same factor. That is 36 should be 3 times the value of ?. Thus ? = 12.
Can you now see what to do with 12/36 and ?/9?