Expanded form counts tens: 1st grade math lesson

What this lesson shows

Fixes a mistake

83 is 80 + 3, not 8 + 3. The 8 stands for 8 tens.

The worked example

The lesson works this one step by step: 83. Then your kid tries one like it on paper.

The steps

The first digit counts tens
Count them by tens
Tens plus ones

Helping at home

The first digit counts tens. Count that many tens by tens, then add the ones: 83 is 80 + 3.

If your kid gets stuck

What does the first digit count?

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 1.NBT.B.2
Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

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

Alabama MA19.1.11a, MA19.1.11c
Alaska 1.CC.4, 1.NBT.2.c
Arizona 1.NBT.B.2.c
Arkansas 1.NPV.3, 1.NPV.4
California 1.NBT.B.2
Colorado 1.NBT.B.2.c
Connecticut 1.NBT.B.2
Delaware 1.NBT.B.2
District of Columbia 1.NBT.B.2
Florida MA.1.NSO.1.2
Georgia 1.NR.1.2
Hawaii 1.NBT.B.2
Idaho 1.NBT.B.2.c
Illinois 1.NBT.B.2
Indiana 1.NS.2
Iowa 1.NBT.B.2.c
Kansas 1.NBT.2.c, 1.NBT.2.d
Kentucky KY.1.NBT.2.c
Louisiana 1.NBT.B.2.c
Maine 1.NBT.B.2c
Maryland 1.NOS.B.3.a, 1.NOS.B.3.b
Massachusetts 1.NBT.B.2.c
Michigan 1.NBT.B.2
Minnesota 1.1.1.1, 1.1.1.2
Mississippi 1.NBT.2.c
Missouri 1.NBT.A.2
Montana MT.1.NBT.1, MT.1.NBT.2
Nebraska 1.N.3.a
Nevada 1.NBT.B.2
New Hampshire 1.NBT.B.2
New Jersey 1.NBT.B.2c
New Mexico 1.NBT.B.2
New York NY-1.NBT.2.c
North Carolina NC.1.NBT.2.c
North Dakota 1.NO.NBT.1
Ohio 1.NBT.2
Oklahoma 1.N.1.2, 1.N.1.3
Oregon 1.NBT.B.2
Pennsylvania CC.2.1.1.B.2
Rhode Island 1.NBT.B.2.c
South Carolina 1.NR.1.2, 1.NR.1.1
South Dakota 1.NBT.B.2.c
Tennessee 1.NBT.B.3
Texas 111.3.b.2.B, 111.3.b.2.C
Utah 1.NBT.2.c
Vermont 1.NBT.B.2
Virginia K.NS.1j, 1.NS.1e, 1.NS.2c, 1.NS.2d
Washington 1.NBT.B.2
West Virginia M.1.10
Wisconsin M.1.NBT.B.2
Wyoming 1.NBT.2c, 1.NBTP.2.C

Expanded form counts tens