New names, same number: 2nd grade math lesson

What this lesson shows

Fixes a mistake

879 as 87 tens and 9 ones is still 879. Regrouping does not change the value.

The worked example

The lesson works this one step by step: 87 tens and 9 ones. Then your kid tries one like it on paper.

The steps

A ten is worth 10
Find what the tens are worth
Add the ones
Same number

Helping at home

Each ten is worth 10, so a number of tens is that many tens times ten. Write what the tens are worth, then add the ones.

If your kid gets stuck

What are the tens worth?

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 2.NBT.A.1
Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:

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

Alabama MA19.2.6a
Alaska 2.NBT.1.a, 2.NBT.1.b
Arizona 2.NBT.A.1.a, 2.NBT.A.1.b
Arkansas 2.NPV.2, 2.NPV.3
California 2.NBT.A.1
Colorado 2.NBT.A.1.a, 2.NBT.A.1.b
Connecticut 2.NBT.A.1
Delaware 2.NBT.A.1
District of Columbia 2.NBT.A.1
Florida MA.2.NSO.1.1, MA.2.NSO.1.2
Georgia 2.NR.1.1
Hawaii 2.NBT.A.1
Idaho 2.NBT.A.1.a, 2.NBT.A.1.b, 2.NBT.A.3
Illinois 2.NBT.A.1
Indiana 2.NS.2, 2.NS.4
Iowa 2.NBT.A.1.a, 2.NBT.A.1.b
Kansas 2.NBT.1.a, 2.NBT.1.b, 2.NBT.1.c, 2.NBT.3
Kentucky KY.2.NBT.1.a, KY.2.NBT.1.b
Louisiana 2.NBT.A.1.a, 2.NBT.A.1.b
Maine 2.NBT.A.1a, 2.NBT.A.1b
Maryland 2.NOS.A.1.a, 2.NOS.A.1.b, 2.NOS.A.1.c
Massachusetts 2.NBT.A.1.a, 2.NBT.A.1.b
Michigan 2.NBT.A.1
Minnesota 2.1.1.1, 2.1.1.2
Mississippi 2.NBT.1.a, 2.NBT.1.b
Missouri 2.NBT.A.1, 2.NBT.A.2, 2.NBT.A.4
Montana MT.2.NBT.1, MT.2.NBT.3
Nebraska 2.N.1.a, 2.N.3.a, 2.N.3.b
Nevada 2.NBT.A.1
New Hampshire 2.NBT.A.1
New Jersey 2.NBT.A.1a, 2.NBT.A.1b
New Mexico 2.NBT.A.1
New York NY-2.NBT.1.a, NY-2.NBT.1.b
North Carolina NC.2.NBT.1.a, NC.2.NBT.1.b, NC.2.NBT.1.c
North Dakota 2.NO.NBT.1, 2.NO.CC.3
Ohio 2.NBT.1.a, 2.NBT.1.b, 2.NBT.3
Oklahoma 2.N.1.1, 2.N.1.3
Oregon 2.NBT.A.1
Pennsylvania CC.2.1.2.B.1
Rhode Island 2.NBT.A.1.a, 2.NBT.A.1.b
South Carolina 2.NR.1.3, 2.NR.1.2, 2.NR.1.1
South Dakota 2.NBT.A.3, 2.NBT.A.1.a, 2.NBT.A.1.b
Tennessee 2.NBT.A.1, 2.NBT.A.3
Texas 111.4.b.2.A, 111.4.b.2.B
Utah 2.NBT.1.a, 2.NBT.1.b
Vermont 2.NBT.A.1
Virginia 2.NS.2a, 2.NS.2b, 2.NS.2c, 2.NS.2d, 2.NS.2e
Washington 2.NBT.A.1
West Virginia M.2.6
Wisconsin M.2.NBT.A.1
Wyoming 2.NBT.1a, 2.NBT.1b, 2.NBT.1c, 2.NBTP.1.A, 2.NBTP.1.B, 2.NBTP.1.C

New names, same number