What a Ratio Is

A fruit bowl holds 3 apples and 4 pears. The ratio of apples to pears is 3 to 4: for every 3 apples there are 4 pears. The same ratio is written three ways: in words, 3 to 4; with a colon, 3:4; and as a fraction, 3/4. All three say the same thing, and you will meet all three.

Order matters. The ratio of pears to apples is 4 to 3, a different ratio. The first number belongs to the first thing named. Swap them and the sentence changes meaning: 3 to 4 says there are fewer apples than pears, 4 to 3 says there are more.

Apples to pears compares one part of the bowl with another part: a part to part ratio. You can also compare a part with the whole. The bowl holds 3 + 4 = 7 pieces of fruit, so apples to all the fruit is 3 to 7, a part to whole ratio. That one is the fraction of the bowl that is apples, 3/7.