Reason with linear proportions

National standard one: Combine simple proportions to work out what parts the whole is made up in a unit of 10 like 3 yellow with 7 blue, 5 yellow with 5 blue, 4 yellow with 6 blue. Say what the fraction and percentage of each stack is for yellow and blue.

National standard two: Combine proportions to work out what parts the whole is made up of using non-multiple of 10 like 8 yellow :5 blue :4 white with 11 yellow :11 blue :11 white (19:16:15 and 38% :32% :30%). 

Here is a screenshot of my progress on the IXL activities.

To figure this out I used cross checking. To do this you multiply the numerator and denominator on both the fractions like a cross as shown in example. If the numbers match at the end they are a proportion