Roots of Reason
Roots of Reason
rootsofreason.org
chunks you already know
Anchor Chart · Grade 4 · 4.NBT.B.6

Division Strategies

672 ÷ 5 take out chunks of 5 you are sure about,
then add the chunks up. every page below is this one problem.
1Think Multiplication
672 ÷ 5 = ?
is asking
5 × ? = 672
5 × 100 = 500
not enough
5 × 200 = 1000
too much
Every division hides a multiplication. Two facts you already know trap the answer between 100 and 200, before you divide.
2Take Out Chunks You Know
672take 100 fives-500172take 20 fives-10072take 10 fives-5022take 4 fives-202nothing left to take100 + 20 + 10 + 4134 R2
Subtract a chunk of fives you are sure of. Bolder chunks finish faster and land in the same place.
3Draw It as a Rectangle
100500301504205134 wide2 left5 × 134 = 670, and 2 more makes 672
The same problem as an area. The height is the divisor, the widths are the chunks. The leftover cannot fill a row.
4What the Remainder Means
672 pencils, 5 to a box.
How many boxes get filled? 134
How many boxes to hold
every single pencil? 135
How many pencils are
still loose at the end? 2
The division is 134 R2 every time. The question decides whether the 2 is dropped, adds a box, or is the answer.