Divide whole numbers by unit fractions using models

Dividing by a unit fraction asks one question: how many of these small pieces fit inside the whole amount? Each whole holds 4 fourths, so 3 wholes hold 12 of them. Counting comes first. The bars make that visible before any rule shows up, and a child who has counted the fourths will later trust the shortcut of multiplying by 4.

Problem 2 is the stretch, with eighteen narrow ninths spread across two bars. That is unit fraction division with models at its most patient.

The standard is 5.NF.B.7.b, dividing a whole number by a unit fraction with a visual model, and all three problems stay inside it.

Hand your child a pencil and say, "Tap every ninth as you count." Tapping keeps the count honest on 2 ÷ 1/9, where the strips are thin and easy to skip.

The likely slip is answering 2/9 or 1/18, because the numbers look like they should shrink. If that happens, point to one bar and ask, "How many ninths make this one whole?" Nine. Then the second bar. Most children say 18 before you finish the sentence.

On the last problem, a quick check works well: "Do ten halves rebuild five bars?" Let your child pair the halves up and see.

In Full House: An Invitation to Fractions by Dayle Ann Dodds, a cake at a busy inn gets shared slice by slice among the guests. Read it, then turn the idea around: if every guest gets half a sandwich, how many guests do 4 sandwiches feed? Your child can draw four rectangles and cut each in half.

The same question waits in the kitchen. Filling a 2-cup measuring cup with a 1/4-cup scoop takes 8 scoops; let your child count them out loud.

Say what you watched: "You counted pieces instead of guessing." Reciprocals come next in the series.