What this lesson shows
Fixes a mistake
3 × 2/5 is 6/5, not 6/15. The pieces stay fifths.
The worked example
The lesson works this one step by step: 3 × 2/5. Then your kid tries one like it on paper.
The steps
- Groups of the fraction
- Count the parts
- The parts stay the same size
- Multiply only the top
Helping at home
Read 3 × 2/5 as 3 groups of 2 fifths and draw them. Count the shaded parts: they are all still fifths. Multiply only the top.
If your kid gets stuck
Draw the groups. What size are the parts?
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 4.NF.B.4b
Understand a multiple of a/b as a multiple of 1/b, and use this understanding to multiply a fraction by a whole number. For example, use a visual fraction model to express 3 × (2/5) as 6 × (1/5), recognizing this product as 6/5. (In general, n × (a/b) = (n × a)/b.)
Matches standards in 47 statesSee each state's code
- Alabama MA19.4.16b
- Alaska 4.NF.4.b
- Arizona 4.NF.B.4.b
- Arkansas 4.CAR.6
- California 4.NF.B.4
- Colorado 4.NF.B.4.a, 4.NF.B.4.b
- Connecticut 4.NF.B.4
- Delaware 4.NF.B.4
- District of Columbia 4.NF.B.4
- Florida MA.4.FR.2.4
- Georgia 5.NR.3.4
- Hawaii 4.NF.B.4
- Idaho 4.NF.B.4.b
- Illinois 4.NF.B.4
- Iowa 4.NF.B.4.b
- Kansas 4.NF.4.b
- Kentucky KY.4.NF.4.a, KY.4.NF.4.b
- Louisiana 4.NF.B.4.b
- Maine 4.NF.B.4b
- Maryland 4.NOS.E.13.c
- Massachusetts 4.NF.B.4.b
- Michigan 4.NF.B.4
- Mississippi 4.NF.4.a, 4.NF.4.b
- Missouri 4.NF.B.7
- Montana MT.4.NF.4.a, MT.4.NF.4.b, 4.D1.9, 4.D2.10, 4.D3.4
- Nebraska 4.N.3.c
- Nevada 4.NF.B.4
- New Hampshire 4.NF.B.4
- New Jersey 4.NF.B.4b
- New Mexico 4.NF.B.4
- New York NY-4.NF.4.a, NY-4.NF.4.b
- North Carolina NC.4.NF.4.a
- North Dakota 4.NO.NF.7
- Ohio 4.NF.4.b
- Oregon 4.NF.B.4
- Pennsylvania CC.2.1.4.C.2
- Rhode Island 4.NF.B.4.b
- South Carolina 4.PAFR.2.3
- South Dakota 4.NF.B.4.b
- Tennessee 4.NF.B.4.b
- Texas 111.7.b.3.I
- Utah 4.NF.4.b
- Vermont 4.NF.B.4
- Virginia 4.CE.3c
- Washington 4.NF.B.4
- West Virginia M.4.15
- Wisconsin M.4.NF.B.4
More in this unit
- Equivalent fractions
- Change both parts, not one
- Comparing with 1/2
- Comparing with a common denominator
- Bigger numbers, not a bigger fraction
- Fractions greater than one
- Breaking a fraction into parts
- Adding and subtracting like fractions
- Why the denominator stays
- Adding mixed numbers
- Subtracting mixed numbers
- Fraction stories, same whole
- A whole number times a fraction
- A fraction of a number
- Fraction times stories
- Simplest form