Math Drill Pages

Adding Fractions with Like Denominators

Twenty-four addition problems where both fractions have the same denominator. In Part A every sum is less than 1. In Part B the sums are greater than 1, and students write them as fractions such as 11/8. The answer key keeps the same denominator as the problem.

Grade
Grade 4
Problems
24
Time
About 15 minutes
Standard
4.NF.B.3a
Download PDF (US Letter) Download PDF (A4)

Two pages: the worksheet, then the answer key. No sign-up needed.

Worksheet preview

Part A: Sums less than 1 Add. Write the answer as a fraction.

  1. 512+112=612
  2. 25+25=45
  3. 69+29=89
  4. 13+13=23
  5. 26+36=56
  6. 25+15=35
  7. 612+512=1112
  8. 14+14=24
  9. 27+47=67
  10. 19+39=49
  11. 110+510=610
  12. 26+16=36
  13. 15+25=35
  14. 39+39=69
  15. 312+812=1112
  16. 18+68=78
  17. 15+35=45
  18. 112+412=512

Part B: Sums greater than 1 Add. Write the answer as a fraction greater than 1.

  1. 46+36=76
  2. 58+68=118
  3. 57+57=107
  4. 39+79=109
  5. 912+512=1412
  6. 710+510=1210

Tips for teachers and parents

  • Ask your student what is being added: fifths plus fifths gives fifths. Only the number of pieces changes, so add the top numbers and keep the bottom number.
  • Use a fraction strip or drawing for the first few problems: 2/5 + 1/5 is two shaded fifths plus one more.
  • In Part B, ask whether the answer is more than one whole. If the top number is bigger than the bottom number, it is.
  • Students who are ready can rewrite Part B answers as mixed numbers, such as 11/8 = 1 3/8.

Common mistakes

  • Adding the denominators too, so 2/5 + 1/5 becomes 3/10. A quick picture shows 3/10 is smaller than 2/5, which cannot be right.
  • Simplifying incorrectly. Simplifying is not required on this sheet, so students can leave answers like 4/6 as they are.

What to practice next

Subtracting fractions with like denominators uses the same idea in reverse.

Frequently asked questions

How do you add fractions with like denominators?

Add the numerators and keep the denominator. For example, 3/8 + 4/8 = 7/8, because 3 eighths plus 4 eighths is 7 eighths.

Do answers need to be simplified?

No. The answer key shows each sum with the same denominator, such as 6/12. A simplified answer like 1/2 is also correct.

Is there an answer key?

Yes, page 2 has all 24 answers.