Knowing how the size of the whole tells a lot of important information about a fraction: half of 24 cookies is not the same as half of 12 brownies. A lot of the trickiest problems are ones where you need to keep track of the size of the whole.

For example, think about this problem: Lori planted some seedlings. Her little brother was playing, and squashed half of the seedlings (they did not survive). Then, her cat ate 1/3 of the seedlings that were left. How many of her seedlings survived?

Try drawing a picture and using numbers both before you look at the answer

That problem was tricky because the cat didn't eat 1/3 of the original number of seedlings, it ate 1/3 of the seedlings left after 1/2 had been squashed.

When you read a word problem, try to be aware of what each of the fractions are fractions of.

Here are some examples about finding parts from wholes

And finding wholes from parts