What this lesson shows
Fixes a mistake
20 × 0.5 = 10, smaller than 20. 20 ÷ 0.5 = 40, bigger: it counts the halves.
The worked example
The lesson works this one step by step: 20 × 0.5. Then your kid tries one like it on paper.
The steps
- Times less than 1: smaller
- Divided by less than 1: bigger
- Ask: more than 1, or less?
Helping at home
Times 0.5 takes half of the number, so it is smaller. Divided by 0.5 counts how many halves fit, so it is bigger. Ask first: is the number you multiply or divide by more than 1, or less?
If your kid gets stuck
Is the decimal less than 1? Then times shrinks and divided by grows.
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.
Standards
- Common Core 5.NBT.B.7
Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
Matches a standard in all 50 states and DCSee each state's code
- Alabama MA19.5.8a, MA19.5.8b
- Alaska 5.NBT.7
- Arizona 5.NBT.B.7 *
- Arkansas 5.CAR.3, 5.CAR.4
- California 5.NBT.B.7
- Colorado 5.NBT.B.7
- Connecticut 5.NBT.B.7
- Delaware 5.NBT.B.7
- District of Columbia 5.NBT.B.7
- Florida MA.5.NSO.2.3, MA.5.NSO.2.4, MA.5.M.2.1
- Georgia 5.NR.4.4
- Hawaii 5.NBT.B.7
- Idaho 5.NBT.A.7.a, 5.NBT.A.7.b
- Illinois 5.NBT.B.7
- Indiana 5.CA.9, 5.CA.10
- Iowa 5.NBT.B.7
- Kansas 5.NBT.7
- Kentucky KY.5.NBT.7.a, KY.5.NBT.7.b
- Louisiana 5.NBT.B.7
- Maine 5.NBT.B.7
- Maryland 5.NOS.B.4.a, 5.NOS.B.5.a, 5.NOS.B.6.b, 5.NOS.B.6.c, 5.NOS.B.6.d, 5.NOS.B.7.a, 5.NOS.B.7.b, 5.NOS.B.7.c, 5.NOS.B.7.d, 5.NOS.B.7.e
- Massachusetts 5.NBT.B.7
- Michigan 5.NBT.B.7
- Minnesota 5.1.1.3, 5.1.3.1, 5.1.3.2, 5.1.3.4
- Mississippi 5.NBT.7
- Missouri 5.NBT.A.6, 5.NBT.A.7, 5.NBT.A.8, 5.NF.B.4, 5.RA.C.5
- Montana MT.5.NBT.7, 5.D1.11, 5.D1.12, 5.D1.13, 5.D2.11, 5.D2.12
- Nebraska 5.N.3.g, 5.A.1.c
- Nevada 5.NBT.B.7
- New Hampshire 5.NBT.B.7
- New Jersey 5.NBT.B.7
- New Mexico 5.NBT.B.7
- New York NY-5.NBT.7
- North Carolina NC.5.NBT.7.a, NC.5.NBT.7.b, NC.5.NBT.7.c, NC.5.NBT.7.d
- North Dakota 5.NO.NBT.5
- Ohio 5.NBT.7.a, 5.NBT.7.b, 5.NBT.7.c
- Oklahoma 5.N.2.1, 5.N.3.2, 5.N.3.3
- Oregon 5.NBT.B.7
- Pennsylvania CC.2.1.5.B.2
- Rhode Island 5.NBT.B.7
- South Carolina 5.PAFR.1.4, 5.PAFR.1.3
- South Dakota 5.NBT.B.7.a, 5.NBT.B.7.b
- Tennessee 5.NBT.B.7
- Texas 111.6.b.4.A, 111.7.b.3.A, 111.7.b.3.D, 111.7.b.3.E, 111.7.b.3.F, 111.7.b.3.G, 111.7.b.3.K
- Utah 5.NBT.7
- Vermont 5.NBT.B.7
- Virginia 4.CE.4a.i, 4.CE.4a.ii, 4.CE.4b, 5.CE.3a, 5.CE.3b.i, 5.CE.3b.ii, 5.CE.3b.iii, 5.CE.3c.i, 5.CE.3c.ii, 5.CE.3c.iii, 5.CE.3c.iv, 5.CE.3d, 5.CE.3e
- Washington 5.NBT.B.7
- West Virginia M.5.10
- Wisconsin M.5.NBT.A.4, M.5.NBT.B.7
- Wyoming 5.NBT.7