Renaming both fractions: 5th grade math lesson

What this lesson shows

2/3 − 1/4: cut both bars until the pieces match, 8/12 − 3/12.

The worked example

The lesson works this one step by step: 2/3 − 1/4. Then your kid tries one like it on paper.

The steps

Find parts that fit both
Rename both fractions
Work the tops, then check

Helping at home

Find a number in both bottoms’ times tables, such as 12 for thirds and fourths. Rename each fraction by multiplying its top and bottom by the same number. Then add or subtract the tops. Check a difference by adding it back.

If your kid gets stuck

Find parts that fit both. Rename both, then work the tops.

Watch it with Lux

With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.

See how Lux works

Standards

Common Core 5.NF.A.1
Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)

Matches standards in 49 statesSee each state's code

Alabama MA19.5.10
Alaska 5.NF.1
Arizona 5.NF.A.1
Arkansas 5.CAR.5
California 5.NF.A.1
Colorado 5.NF.A.1
Connecticut 5.NF.A.1
Delaware 5.NF.A.1
District of Columbia 5.NF.A.1
Florida MA.5.FR.2.1
Georgia 5.NR.3.3
Hawaii 5.NF.A.1
Idaho 5.NF.A.1
Illinois 5.NF.A.1
Indiana 5.CA.3
Iowa 5.NF.A.1
Kansas 5.NF.1
Kentucky KY.5.NF.1
Louisiana 5.NF.A.1
Maine 5.NF.A.1
Maryland 5.NOS.C.8.b, 5.NOS.C.8.c
Massachusetts 5.NF.A.1
Michigan 5.NF.A.1
Minnesota 5.1.3.1, 5.1.3.2
Mississippi 5.NF.1
Missouri 5.NF.B.6
Montana MT.5.NF.1, 5.D2.5, 5.D3.4
Nebraska 5.N.3.e
Nevada 5.NF.A.1
New Hampshire 5.NF.A.1
New Jersey 5.NF.A.1
New Mexico 5.NF.A.1
New York NY-5.NF.1
North Dakota 5.NO.NF.3
Ohio 5.NF.1
Oklahoma 5.N.3.3
Oregon 5.NF.A.1
Pennsylvania CC.2.1.5.C.1
Rhode Island 5.NF.A.1
South Carolina 5.PAFR.2.1, 5.PAFR.3.1
South Dakota 5.NF.A.1
Tennessee 5.NF.A.1
Texas 111.7.b.3.H, 111.7.b.3.K
Utah 5.NF.1
Vermont 5.NF.A.1
Virginia 5.CE.2a, 5.CE.2b
Washington 5.NF.A.1
West Virginia M.5.11
Wisconsin M.5.NF.A.1

Renaming both fractions