# Spectrum Math Grade 5 Chapter 5 Lesson 3 Answer Key Subtracting Fractions with Unlike Denominators

Practice with the help of Spectrum Math Grade 5 Answer Key Chapter 5 Lesson 5.3 Subtracting Fractions with Unlike Denominators regularly and improve your accuracy in solving questions.

## Spectrum Math Grade 5 Chapter 5 Lesson 5.3 Subtracting Fractions with Unlike Denominators Answers Key

When subtracting fractions that have different denominators, rename fractions to have a common denominator. Then, subtract fractions, and write the difference in simplest form. Subtract. Write answers in simplest form.

Question 1.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{3}{4}$$ – $$\frac{1}{2}$$
LCD is 4.
$$\frac{3}{4}$$ – $$\frac{2}{4}$$ = $$\frac{1}{4}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{6}$$ – $$\frac{1}{3}$$
LCD is 6
$$\frac{5}{6}$$ – $$\frac{2}{6}$$ = $$\frac{3}{6}$$ = $$\frac{1}{2}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{9}{10}$$ – $$\frac{2}{5}$$
LCD is 10
$$\frac{9}{10}$$ – $$\frac{4}{10}$$ = $$\frac{5}{10}$$ = $$\frac{1}{2}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{4}{7}$$ – $$\frac{1}{8}$$
LCD is 56
$$\frac{32}{56}$$ – $$\frac{7}{56}$$ = $$\frac{25}{56}$$ e. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{9}$$ – $$\frac{1}{3}$$
LCD is 9
$$\frac{5}{9}$$ – $$\frac{1}{3}$$ = $$\frac{2}{9}$$ Question 2.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{2}{5}$$ – $$\frac{1}{9}$$
LCD is 45.
$$\frac{18}{45}$$ – $$\frac{5}{45}$$ = $$\frac{13}{45}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{3}{5}$$ – $$\frac{2}{7}$$
LCD is 35.
$$\frac{21}{35}$$ – $$\frac{10}{35}$$ = $$\frac{11}{35}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{2}{3}$$ – $$\frac{3}{8}$$
LCD is 24
$$\frac{16}{24}$$ – $$\frac{9}{24}$$ = $$\frac{7}{24}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{6}$$ – $$\frac{1}{3}$$
LCD is 6
$$\frac{5}{6}$$ – $$\frac{2}{6}$$ = $$\frac{3}{6}$$ = $$\frac{1}{2}$$ e. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{3}{4}$$ – $$\frac{2}{9}$$
LCD is 36
$$\frac{27}{36}$$ – $$\frac{8}{36}$$ = $$\frac{19}{36}$$ Question 3.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{7}{10}$$ – $$\frac{3}{6}$$
LCD is 30
$$\frac{21}{30}$$ – $$\frac{15}{30}$$ = $$\frac{6}{30}$$ = $$\frac{1}{5}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{8}{9}$$ – $$\frac{1}{4}$$
LCD is 36
$$\frac{32}{36}$$ – $$\frac{9}{36}$$ = $$\frac{23}{36}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{7}{8}$$ – $$\frac{5}{12}$$
LCD is 24
$$\frac{21}{24}$$ – $$\frac{10}{24}$$ = $$\frac{11}{24}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{7}{10}$$ – $$\frac{1}{4}$$
LCD is 20
$$\frac{14}{20}$$ – $$\frac{5}{20}$$ = $$\frac{9}{20}$$ e. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{4}{5}$$ – $$\frac{3}{7}$$
LCD is 35
$$\frac{28}{35}$$ – $$\frac{15}{35}$$ = $$\frac{13}{35}$$ Subtract. Write answers in simplest form.

Question 1.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{9}$$ – $$\frac{5}{18}$$
LCD is 18
$$\frac{10}{18}$$ – $$\frac{5}{18}$$ = $$\frac{5}{18}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator. $$\frac{5}{8}$$ – $$\frac{3}{12}$$
LCD is 24
$$\frac{15}{24}$$ – $$\frac{6}{24}$$ = $$\frac{9}{24}$$ = $$\frac{3}{8}$$

c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{7}{18}$$ – $$\frac{3}{9}$$
LCD is 18
$$\frac{7}{18}$$ – $$\frac{6}{18}$$ = $$\frac{1}{18}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{4}{8}$$ – $$\frac{7}{16}$$
LCD is 16
$$\frac{8}{16}$$ – $$\frac{7}{16}$$ = $$\frac{1}{16}$$ Question 2.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{10}$$ – $$\frac{1}{15}$$
LCD is 30
$$\frac{15}{30}$$ – $$\frac{2}{30}$$ = $$\frac{13}{30}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{9}{18}$$ – $$\frac{2}{15}$$
LCD is 90
$$\frac{45}{90}$$ – $$\frac{12}{90}$$ = $$\frac{33}{90}$$ = $$\frac{11}{30}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{9}{10}$$ – $$\frac{9}{14}$$
LCD is 70
$$\frac{63}{70}$$ – $$\frac{45}{70}$$ = $$\frac{18}{70}$$ = $$\frac{18}{70}$$ = $$\frac{9}{35}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{6}{16}$$ – $$\frac{1}{8}$$
LCD is 16
$$\frac{6}{16}$$ – $$\frac{2}{16}$$ = $$\frac{4}{16}$$ = $$\frac{1}{4}$$ Question 3.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{8}$$ – $$\frac{1}{9}$$
LCD is 72
$$\frac{45}{72}$$ – $$\frac{8}{72}$$ = $$\frac{37}{72}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{7}{10}$$ – $$\frac{7}{15}$$
LCD is 30
$$\frac{21}{30}$$ – $$\frac{14}{30}$$ = $$\frac{7}{30}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{8}{36}$$ – $$\frac{3}{14}$$
LCD is 252
$$\frac{56}{252}$$ – $$\frac{54}{252}$$ = $$\frac{2}{252}$$ = $$\frac{1}{126}$$ d. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{13}{36}$$ – $$\frac{9}{35}$$
LCD is 1260
$$\frac{455}{1260}$$ – $$\frac{324}{1260}$$ = $$\frac{131}{1260}$$ Question 4.
a. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{10}{25}$$ – $$\frac{2}{9}$$
LCD is 225
$$\frac{90}{225}$$ – $$\frac{50}{225}$$ = $$\frac{40}{225}$$ = $$\frac{8}{45}$$ b. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{5}{24}$$ – $$\frac{3}{15}$$
LCD is 120
$$\frac{25}{120}$$ – $$\frac{24}{120}$$ = $$\frac{1}{120}$$ c. When subtracting fractions that have different denominators, rename fractions to have a common denominator.
$$\frac{1}{8}$$ – $$\frac{3}{26}$$
LCD is 104
$$\frac{13}{104}$$ – $$\frac{12}{104}$$ = $$\frac{1}{104}$$ d. $$\frac{9}{14}$$ – $$\frac{1}{8}$$
$$\frac{36}{104}$$ – $$\frac{7}{56}$$ = $$\frac{29}{56}$$ 