Fractions of whole number exercises

Taking a fraction of a whole number is two small jobs: split the number into equal parts, then keep some of them. Five-ninths of 150 means 150 split into nine parts with five of them kept, which lands on 83 1/3.

The worked example shows the move the page wants every time. Write the whole number over 1, multiply straight across, then simplify: 6/1 × 10/15 gives 60/15, and 60/15 is 4. After that, the instructions rotate between whole numbers, mixed numbers and improper fractions. Read first, then multiply.

The standard is 5.NF.B.4.a, reading (a/b) × q as a parts of q split into b equal parts.

Problem 2 is where the classic slip shows up. Some children multiply the denominator by 6 as well and write 30/72. Ask, "How many twelfths do six groups of 5/12 make?" Thirty twelfths, which is 2 1/2.

A note for parents: the answer page gives 3 3/4 for problem 2, and the correct value is 2 1/2. Problem 3 on the student page repeats 6 × 5/12, while the answer page solves 8 × 3/40 = 3/5 instead. Let your child solve what is printed and check it with you.

Problem 4 asks for an improper fraction, so 84/29 is the target, yet the key prints 2 26/29. Say, "Both are right. Which form did the line ask for?"

Groceries hand you this math constantly. A $12 bag of oranges sells at 3/4 of the price, and your child writes 12/1 × 3/4 to find $9 before the cashier does. In the car, if a 150-mile trip is 2/3 done, how many miles are behind you? A hundred.

Read Full House: An Invitation to Fractions by Dayle Ann Dodds together; every guest who arrives at the inn is a fraction of the full house.

Thank the work, not the speed: "You wrote the whole number over 1 every time." Next in the series comes finding fractions of whole numbers, where your child picks the product that hits a target.