Explanation:
We are asked to decompose fractions into sums of
unit fractions — that is, fractions with numerator 1.
A unit fraction looks like:
$\frac{1}{n}$, where $n$ is a whole number.
To decompose a fraction like $\frac{a}{b}$ (where $a < b$ or $a > b$), we write it as a sum of $a$ copies of $\frac{1}{b}$, *if* the denominator stays the same.
This works because:
$$
\frac{a}{b} = \underbrace{\frac{1}{b} + \frac{1}{b} + \cdots + \frac{1}{b}}_{a \text{ times}}
$$
Let’s go through each part:
---
Part A: Express each fraction as a sum of unit fractions
1) $\frac{8}{9}$
→ 8 copies of $\frac{1}{9}$:
$\frac{1}{9} + \frac{1}{9} + \frac{1}{9} + \frac{1}{9} + \frac{1}{9} + \frac{1}{9} + \frac{1}{9} + \frac{1}{9}$
✔ Already given in the problem — just confirm it's correct.
2) $\frac{5}{6}$
→ 5 copies of $\frac{1}{6}$:
$\frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6}$
3) $\frac{2}{3}$
→ 2 copies of $\frac{1}{3}$:
$\frac{1}{3} + \frac{1}{3}$
4) $\frac{4}{7}$
→ 4 copies of $\frac{1}{7}$:
$\frac{1}{7} + \frac{1}{7} + \frac{1}{7} + \frac{1}{7}$
5) $\frac{9}{10}$
→ 9 copies of $\frac{1}{10}$:
$\frac{1}{10} + \frac{1}{10} + \cdots + \frac{1}{10}$ (9 times)
6) $\frac{3}{5}$
→ 3 copies of $\frac{1}{5}$:
$\frac{1}{5} + \frac{1}{5} + \frac{1}{5}$
All of these follow the pattern: numerator tells you how many unit fractions to add, and denominator stays the same.
---
Part B: Choose the correct expression
1) Which shows $\frac{7}{8}$ decomposed?
Let’s count how many $\frac{1}{8}$ terms are in each option:
a) $\frac{1}{8} + \frac{1}{8} + \frac{1}{8} + \frac{1}{8} + \frac{1}{8} + \frac{1}{8} + \frac{1}{8}$ → that’s
7 terms → correct!
b) Has 8 terms → $\frac{8}{8} = 1$, too big.
c) Only 4 terms → $\frac{4}{8} = \frac{1}{2}$, too small.
d) Only 3 terms → $\frac{3}{8}$, too small.
So answer is
a).
2) Which shows $\frac{6}{11}$ decomposed?
Count the $\frac{1}{11}$ terms:
a) 6 terms → $\frac{6}{11}$
✔
b) 3 terms → $\frac{3}{11}$
c) 3 terms → $\frac{3}{11}$
d) 5 terms → $\frac{5}{11}$
So answer is
a).
Double-check:
- For $\frac{6}{11}$, we need six $\frac{1}{11}$’s. Option a has exactly six:
$\frac{1}{11} + \frac{1}{11} + \frac{1}{11} + \frac{1}{11} + \frac{1}{11} + \frac{1}{11}$
Yes.
Final Answer:
A)
2) $\frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6}$
3) $\frac{1}{3} + \frac{1}{3}$
4) $\frac{1}{7} + \frac{1}{7} + \frac{1}{7} + \frac{1}{7}$
5) $\frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10} + \frac{1}{10}$
6) $\frac{1}{5} + \frac{1}{5} + \frac{1}{5}$
B)
1) a
2) a
Parent Tip: Review the logic above to help your child master the concept of decomposing fractions worksheet 4th grade.