Roots of Reason
Roots of Reason
rootsofreason.org
words → lengths
Anchor Chart · Grades 3-5 · 3.OA.D.8 | 4.OA.A.2

Tape Diagrams

One picture that fits every operation - the ? shows exactly what the problem is hiding.
Addition - part + part, whole unknown
90
60
?
90 + 60 = ?
Subtraction - one part is missing
90
?
150
150 − 90 = ?  or  90 + ? = 150
Comparison - "60 more than"
James
90
Emily
90
60
Emily solved 90 + 60 = ?
Multiplication - equal parts, whole unknown
30
30
30
30
30
30
?
30 × 6 = ?
Division - whole known, parts unknown
180
?
?
?
?
?
?
180 ÷ 6 = ?  or  6 × ? = 180
How to Read a Tape
· The whole is one long bar.
· Parts share a bar, side by side. Equal parts are the same length.
· The ? marks what the problem hides - find it before you compute.
· Same lengths, different question → different operation.