Comparing with a common denominator: 4th grade math lesson

What this lesson shows

2/3 and 3/4 renamed in twelfths, then compared.

The worked example

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

The steps

Find a common denominator
Rename both fractions
Same parts: compare the tops

Helping at home

Find a denominator both bottoms fit into, using the times tables. Rename each fraction by multiplying its top and bottom by the same number. With the same parts, the bigger top is the bigger fraction.

If your kid gets stuck

Write <, >, or =. Rename both in the same parts first.

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 4.NF.A.2
Compare two fractions with different numerators and different denominators, e.g., by creating common denominators or numerators, or by comparing to a benchmark fraction such as 1/2. Recognize that comparisons are valid only when the two fractions refer to the same whole. Record the results of comparisons with symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction model.

Matches a standard in all 50 states and DCSee each state's code

Alabama MA19.4.14a
Alaska 4.NF.2
Arizona 4.NF.A.2.a, 4.NF.A.2.b
Arkansas 4.NPV.5
California 4.NF.A.2
Colorado 4.NF.A.2
Connecticut 4.NF.A.2
Delaware 4.NF.A.2
District of Columbia 4.NF.A.2
Florida MA.4.FR.1.4
Georgia 4.NR.4.3, 5.NR.3.2
Hawaii 4.NF.A.2
Idaho 4.NF.A.2.a, 4.NF.A.2.b
Illinois 4.NF.A.2
Indiana 4.NS.4, 5.NS.1
Iowa 4.NF.A.2
Kansas 4.NF.2
Kentucky KY.4.NF.2
Louisiana 4.NF.A.2
Maine 4.NF.A.2
Maryland 4.NOS.D.10.a, 4.NOS.D.10.b, 4.NOS.D.10.c
Massachusetts 4.NF.A.2
Michigan 4.NF.A.2
Minnesota 4.1.2.2, 5.1.2.3
Mississippi 4.NF.2
Missouri 4.NF.A.3, 5.NF.A.3
Montana MT.4.NF.2, 4.D1.2
Nebraska 4.N.2.c, 5.N.2.b
Nevada 4.NF.A.2
New Hampshire 4.NF.A.2
New Jersey 4.NF.A.2
New Mexico 4.NF.A.2
New York NY-4.NF.2
North Carolina NC.4.NF.2.a, NC.4.NF.2.b, NC.4.NF.2.c
North Dakota 4.NO.NF.5
Ohio 4.NF.2
Oklahoma 4.N.3.2, 4.N.3.3, 5.N.1.3
Oregon 4.NF.A.2
Pennsylvania CC.2.1.4.C.1
Rhode Island 4.NF.A.2
South Carolina 4.NR.2.6, 5.NR.2.1
South Dakota 4.NF.A.2
Tennessee 4.NF.A.2
Texas 111.6.b.3.D, 111.6.b.3.G
Utah 4.NF.2
Vermont 4.NF.A.2
Virginia 3.NS.3e, 5.NS.1d, 4.NS.3a, 4.NS.3b, 4.NS.3c, 4.NS.3d
Washington 4.NF.A.2
West Virginia M.4.13
Wisconsin M.4.NF.A.2
Wyoming 4.NF.2a, 4.NF.2b, 4.NF.2c, 4.NFP.2.A, 4.NFP.2.B, 4.NFP.2.C

Comparing with a common denominator