Multiplying a fraction and a whole number

Practice 3 items →

Two readings of the same symbols: n times a/b as repeated addition, and a/b of N as a part of a set. Students compute both and use a bar model for fraction-of-a-quantity stories, including two-stage ones.

Specification · for a parent or teacher

Part no.: fraction-times-whole
Course: Advanced Math 4 · Unit 8
Realm: Foundations
Difficulty: 2 of 4 — Grade 4–5. Two steps, or one idea in a story.
Qty: 3 items

Part no. is the node's id; the realm is the kind of math; qty is how many practice items it carries.

Students can

compute $n \times \frac{a}{b} = \frac{n\cdot a}{b}$ and $\frac{a}{b}$ of $N$ ; use a bar model for a fraction-of-a-quantity story.

Ready when

“ $\frac34$ of the 28 beads are red; $\frac13$ of the red beads are large” — they can find the large red beads.

Formulas

Fraction times whole

n \times \frac{a}{b} = \frac{n\cdot a}{b}

Watch for

$\frac23$ of 12 drawn as two of three items instead of two of three equal parts of the bar.

Before · requires

Fractionsfraction-fundamentals · Math 4
Multiplicationmulti-digit-multiplication · Math 4

After · used by

Multiplying fractionsfraction-mul-div · Math 5
Ratioratio-tape-diagrams · Math 5

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