Practice worksheet for adding and subtracting rational expressions with algebraic fractions.
Worksheet titled "Adding and Subtracting Rational Expressions" with 12 math problems involving fractions with variables and algebraic expressions.
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Step-by-step solution for: Algebra Tutorial & Worksheets: Adding and Subtracting Rational Expressions
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Show Answer Key & Explanations
Step-by-step solution for: Algebra Tutorial & Worksheets: Adding and Subtracting Rational Expressions
Let’s solve each problem step by step. We’re adding or subtracting rational expressions (fractions with variables or numbers). The key is: if denominators are the same, just add/subtract numerators. If not, find a common denominator first.
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Problem 1:
$\frac{7}{8} + \frac{1}{8}$
Same denominator → add numerators: $7 + 1 = 8$
So: $\frac{8}{8} = 1$
✔ Final for #1: 1
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Problem 2:
$\frac{9}{13} - \frac{5}{13}$
Same denominator → subtract numerators: $9 - 5 = 4$
So: $\frac{4}{13}$ — already simplified.
✔ Final for #2: $\frac{4}{13}$
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Problem 3:
$\frac{11}{20} - \frac{3}{20}$
Same denominator → $11 - 3 = 8$ → $\frac{8}{20}$
Simplify: divide numerator and denominator by 4 → $\frac{2}{5}$
✔ Final for #3: $\frac{2}{5}$
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Problem 4:
$\frac{8}{11} + \frac{3}{11}$
Same denominator → $8 + 3 = 11$ → $\frac{11}{11} = 1$
✔ Final for #4: 1
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Problem 5:
$\frac{x}{x^2} + \frac{y}{x^2}$
Same denominator → combine numerators: $\frac{x + y}{x^2}$
Can we simplify? Not unless x+y shares factor with x² — no info, so leave as is.
But wait — $\frac{x}{x^2} = \frac{1}{x}$, but since both terms have same denominator, better to keep combined.
Actually, let’s check:
$\frac{x + y}{x^2}$ — this is simplest form unless told otherwise.
✔ Final for #5: $\frac{x + y}{x^2}$
Wait — maybe they want it split? No, instruction says “combine like terms in numerator” — so yes, $\frac{x + y}{x^2}$ is correct.
BUT — note: $\frac{x}{x^2} = \frac{1}{x}$, and $\frac{y}{x^2}$ stays — but that would be different denominators. Since original has same denominator, we must combine numerators.
So yes: $\frac{x + y}{x^2}$
However, sometimes you can reduce if possible — here, no common factors between (x+y) and x² unless specified. So leave as is.
✔ Still: $\frac{x + y}{x^2}$
---
Problem 6:
$\frac{8}{x} + \frac{x}{x}$
Second term: $\frac{x}{x} = 1$, but let’s do it properly.
Common denominator is x.
First term: $\frac{8}{x}$
Second term: $\frac{x}{x} = \frac{x}{x}$ → so total: $\frac{8 + x}{x}$
Which is $\frac{x + 8}{x}$ — can write as $1 + \frac{8}{x}$, but instructions say “simplified form” — usually meaning single fraction unless specified.
Check: $\frac{8 + x}{x} = \frac{x + 8}{x}$ — that’s fine.
Is it reducible? Only if x divides x+8 — which it doesn’t generally. So leave as $\frac{x + 8}{x}$
Alternatively, some might prefer splitting: $1 + \frac{8}{x}$ — but the problem says “add or subtract... combining like terms in the numerator” — so probably expects single fraction.
Looking at other problems, they kept single fractions. So:
✔ Final for #6: $\frac{x + 8}{x}$
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Problem 7:
$\frac{12}{7} + \frac{5}{7} + \frac{8}{7}$
All same denominator → add numerators: $12 + 5 + 8 = 25$
So: $\frac{25}{7}$ — improper fraction, but acceptable unless mixed number required. Problem doesn’t specify, so leave as is.
✔ Final for #7: $\frac{25}{7}$
---
Problem 8:
$\frac{7p}{10} + \frac{7p}{10}$
Same denominator → $7p + 7p = 14p$ → $\frac{14p}{10}$
Simplify: divide numerator and denominator by 2 → $\frac{7p}{5}$
✔ Final for #8: $\frac{7p}{5}$
---
Problem 9:
$\frac{7}{2a} + \frac{3}{2a} + \frac{4}{2a}$
Same denominator → add numerators: $7 + 3 + 4 = 14$ → $\frac{14}{2a}$
Simplify: divide numerator and denominator by 2 → $\frac{7}{a}$
✔ Final for #9: $\frac{7}{a}$
---
Problem 10:
$\frac{9}{5a} - \frac{5}{5a}$
Same denominator → $9 - 5 = 4$ → $\frac{4}{5a}$ — already simplified.
✔ Final for #10: $\frac{4}{5a}$
---
Now, compiling all final answers:
Final Answer:
1. 1
2. $\frac{4}{13}$
3. $\frac{2}{5}$
4. 1
5. $\frac{x + y}{x^2}$
6. $\frac{x + 8}{x}$
7. $\frac{25}{7}$
8. $\frac{7p}{5}$
9. $\frac{7}{a}$
10. $\frac{4}{5a}$
---
Problem 1:
$\frac{7}{8} + \frac{1}{8}$
Same denominator → add numerators: $7 + 1 = 8$
So: $\frac{8}{8} = 1$
✔ Final for #1: 1
---
Problem 2:
$\frac{9}{13} - \frac{5}{13}$
Same denominator → subtract numerators: $9 - 5 = 4$
So: $\frac{4}{13}$ — already simplified.
✔ Final for #2: $\frac{4}{13}$
---
Problem 3:
$\frac{11}{20} - \frac{3}{20}$
Same denominator → $11 - 3 = 8$ → $\frac{8}{20}$
Simplify: divide numerator and denominator by 4 → $\frac{2}{5}$
✔ Final for #3: $\frac{2}{5}$
---
Problem 4:
$\frac{8}{11} + \frac{3}{11}$
Same denominator → $8 + 3 = 11$ → $\frac{11}{11} = 1$
✔ Final for #4: 1
---
Problem 5:
$\frac{x}{x^2} + \frac{y}{x^2}$
Same denominator → combine numerators: $\frac{x + y}{x^2}$
Can we simplify? Not unless x+y shares factor with x² — no info, so leave as is.
But wait — $\frac{x}{x^2} = \frac{1}{x}$, but since both terms have same denominator, better to keep combined.
Actually, let’s check:
$\frac{x + y}{x^2}$ — this is simplest form unless told otherwise.
✔ Final for #5: $\frac{x + y}{x^2}$
Wait — maybe they want it split? No, instruction says “combine like terms in numerator” — so yes, $\frac{x + y}{x^2}$ is correct.
BUT — note: $\frac{x}{x^2} = \frac{1}{x}$, and $\frac{y}{x^2}$ stays — but that would be different denominators. Since original has same denominator, we must combine numerators.
So yes: $\frac{x + y}{x^2}$
However, sometimes you can reduce if possible — here, no common factors between (x+y) and x² unless specified. So leave as is.
✔ Still: $\frac{x + y}{x^2}$
---
Problem 6:
$\frac{8}{x} + \frac{x}{x}$
Second term: $\frac{x}{x} = 1$, but let’s do it properly.
Common denominator is x.
First term: $\frac{8}{x}$
Second term: $\frac{x}{x} = \frac{x}{x}$ → so total: $\frac{8 + x}{x}$
Which is $\frac{x + 8}{x}$ — can write as $1 + \frac{8}{x}$, but instructions say “simplified form” — usually meaning single fraction unless specified.
Check: $\frac{8 + x}{x} = \frac{x + 8}{x}$ — that’s fine.
Is it reducible? Only if x divides x+8 — which it doesn’t generally. So leave as $\frac{x + 8}{x}$
Alternatively, some might prefer splitting: $1 + \frac{8}{x}$ — but the problem says “add or subtract... combining like terms in the numerator” — so probably expects single fraction.
Looking at other problems, they kept single fractions. So:
✔ Final for #6: $\frac{x + 8}{x}$
---
Problem 7:
$\frac{12}{7} + \frac{5}{7} + \frac{8}{7}$
All same denominator → add numerators: $12 + 5 + 8 = 25$
So: $\frac{25}{7}$ — improper fraction, but acceptable unless mixed number required. Problem doesn’t specify, so leave as is.
✔ Final for #7: $\frac{25}{7}$
---
Problem 8:
$\frac{7p}{10} + \frac{7p}{10}$
Same denominator → $7p + 7p = 14p$ → $\frac{14p}{10}$
Simplify: divide numerator and denominator by 2 → $\frac{7p}{5}$
✔ Final for #8: $\frac{7p}{5}$
---
Problem 9:
$\frac{7}{2a} + \frac{3}{2a} + \frac{4}{2a}$
Same denominator → add numerators: $7 + 3 + 4 = 14$ → $\frac{14}{2a}$
Simplify: divide numerator and denominator by 2 → $\frac{7}{a}$
✔ Final for #9: $\frac{7}{a}$
---
Problem 10:
$\frac{9}{5a} - \frac{5}{5a}$
Same denominator → $9 - 5 = 4$ → $\frac{4}{5a}$ — already simplified.
✔ Final for #10: $\frac{4}{5a}$
---
Now, compiling all final answers:
Final Answer:
1. 1
2. $\frac{4}{13}$
3. $\frac{2}{5}$
4. 1
5. $\frac{x + y}{x^2}$
6. $\frac{x + 8}{x}$
7. $\frac{25}{7}$
8. $\frac{7p}{5}$
9. $\frac{7}{a}$
10. $\frac{4}{5a}$
Parent Tip: Review the logic above to help your child master the concept of adding and subtracting rational expressions worksheet answers.