Adding fractions with unlike denominators

  • Level: Grade 5
  • Free
  • Printable
  • Answer key included

Students must first rewrite both fractions with a common denominator, ideally the least common multiple. This is a core fifth-grade standard (Common Core 5.NF.A.1).

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Adding fractions with unlike denominators
Name: Date: Score: / 16

Add. Simplify your answer.

  1. 1.
    13+34=
  2. 2.
    110+49=
  3. 3.
    15+14=
  4. 4.
    17+56=
  5. 5.
    18+17=
  6. 6.
    23+110=
  7. 7.
    24+510=
  8. 8.
    34+56=
  9. 9.
    25+39=
  10. 10.
    210+79=
  11. 11.
    25+46=
  12. 12.
    28+23=
  13. 13.
    37+46=
  14. 14.
    47+910=
  15. 15.
    25+48=
  16. 16.
    12+34=
MathSheetLabWorksheet #749493
Adding fractions with unlike denominators Answer key
  1. 1.
    13+34=1112
  2. 2.
    110+49=4990
  3. 3.
    15+14=920
  4. 4.
    17+56=4142
  5. 5.
    18+17=1556
  6. 6.
    23+110=2330
  7. 7.
    24+510=1
  8. 8.
    34+56=1712
  9. 9.
    25+39=1115
  10. 10.
    210+79=4445
  11. 11.
    25+46=1115
  12. 12.
    28+23=1112
  13. 13.
    37+46=1221
  14. 14.
    47+910=13370
  15. 15.
    25+48=910
  16. 16.
    12+34=114
MathSheetLabWorksheet #749493

About this worksheet

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Worked example

47+46=
  1. Find a common denominator: the least common multiple of 7 and 6 is 42.
  2. Rewrite both fractions: 4/7 = 24/42 and 4/6 = 28/42.
  3. Add the numerators: 24 + 28 = 52, so the result is 52/42.
  4. Simplify: divide the top and bottom by 2. 52/42 = 26/21.
  5. 26/21 is more than 1: 26 ÷ 21 = 1 remainder 5, so 26/21 = 1 and 5/21.

Answer: 1 and 5/21

Teaching tips

  • Multiplying the two denominators always works; finding the LCM keeps numbers smaller.

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