Adding and subtracting like fractions: 4th grade math lesson

What this lesson shows

3/8 + 4/8 as jumps on a number line.

The worked example

The lesson works this one step by step: 3/8 + 4/8. Then your kid tries one like it on paper.

The steps

Cut the line in the parts
Jump forward to add, back to subtract
Add the tops, keep the bottom

Helping at home

Draw a number line cut in the fraction’s parts. Jump the first fraction, then jump forward to add or back to subtract. Say the parts out loud: eighths and eighths are still eighths.

If your kid gets stuck

Jump on a number line. The bottom stays the same.

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.B.3a
Understand addition and subtraction of fractions as joining and separating parts referring to the same whole.

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

Alabama MA19.4.15b
Alaska 4.NF.3.a
Arizona 4.NF.B.3.a, 4.NF.A.2.b
Arkansas 4.NPV.5, 4.CAR.5
California 4.NF.B.3
Colorado 4.NF.B.3.a
Connecticut 4.NF.B.3
Delaware 4.NF.B.3
District of Columbia 4.NF.B.3
Florida MA.4.FR.2.2
Georgia 4.NR.4.3, 4.NR.4.4, 4.NR.4.6, 5.NR.3.2
Hawaii 4.NF.B.3
Idaho 4.NF.A.2.b, 4.NF.B.3.a
Illinois 4.NF.B.3
Indiana 5.NS.1, 4.CA.6
Iowa 4.NF.A.2, 4.NF.B.3.a, 4.NF.B.3.c
Kansas 4.NF.3.a
Kentucky KY.4.NF.3.a, KY.4.NF.3.b, KY.4.NF.3.c, KY.4.NF.2
Louisiana 4.NF.B.3.a, 4.NF.B.3.b
Maine 4.NF.B.3a
Maryland 4.NOS.D.10.a, 4.NOS.E.12.a, 4.NOS.E.12.b, 4.NOS.E.12.c
Massachusetts 4.NF.B.3.a
Michigan 4.NF.B.3
Minnesota 4.1.2.2, 4.1.2.3, 5.1.2.3
Mississippi 4.NF.3.a
Missouri 4.NF.A.3, 4.NF.B.4, 5.NF.A.3
Montana MT.4.NF.3.a, MT.4.NF.3.c, 4.D1.2, 4.D2.6, 4.D4.1, 4.D5
Nebraska 4.N.2.c, 4.N.3.b, 4.N.3.c, 5.N.2.b
Nevada 4.NF.B.3
New Hampshire 4.NF.B.3
New Jersey 4.NF.B.3a
New Mexico 4.NF.B.3
New York NY-4.NF.2, NY-4.NF.3.a, NY-4.NF.3.c
North Carolina NC.4.NF.3.a
North Dakota 4.NO.NF.5
Ohio 4.NF.3.a
Oklahoma 4.N.3.2, 4.N.3.3, 4.N.3.5, 5.N.1.3
Oregon 4.NF.A.2, 4.NF.B.3
Pennsylvania CC.2.1.4.C.2
Rhode Island 4.NF.B.3.a
South Carolina 4.NR.2.4, 4.NR.2.6, 5.NR.2.1, 4.PAFR.2.1, 3.NR.2.4, 4.NR.2.5
South Dakota 4.NF.B.3.a
Tennessee 4.NF.A.2, 4.NF.B.3.a
Texas 111.6.b.3.A, 111.6.b.3.D, 111.6.b.3.E, 111.6.b.3.F, 111.6.b.3.G
Utah 4.NF.3.a, 4.NF.3.c
Vermont 4.NF.B.3
Virginia 3.NS.3b, 3.NS.3e, 4.NS.3a, 4.NS.3b, 4.NS.3c, 4.NS.3d, 4.CE.3a
Washington 4.NF.B.3
West Virginia M.4.14
Wisconsin M.4.NF.A.2, M.4.NF.B.3
Wyoming 4.NF.2a, 4.NF.2b, 4.NFP.2.A, 4.NFP.2.B, 4.NF.3a, 4.NFP.3.A

Adding and subtracting like fractions