Grade 4Multi-Digit Multiplication4.OA.A.2

Comparison Word Problems

Decide whether a comparison is "more than" or "times as many," then solve.

Not started Jump to practice

Comparison stories come in two kinds. Some say "more than" (an amount added on). Others say "times as many" (copies of an amount), which you met in Times as Many. The words tell you which operation to use.

Key idea

"$d$ more than" compares by adding or subtracting. "$k$ times as many" compares by multiplying or dividing. To find the smaller amount from the larger one, undo the comparison.

Why it works

Picture two tapes. With "6 more," the longer tape is the shorter tape plus an extra piece of 6. With "3 times as long," the longer tape is 3 copies of the shorter tape. Different pictures, different math.
"More than": the red tape is the blue tape plus an extra piece.
"Times as long": the red tape is 3 copies of the blue tape.

Worked example: Times as many

A blue ribbon is 6 cm long. A red ribbon is 3 times as long. How long is the red ribbon?
  1. "3 times as long" means 3 copies of 6 cm.
  2. $3 \times 6 = 18$.

Answer: 18 cm

Worked example: More than

A blue ribbon is 18 cm long. A red ribbon is 6 cm longer. How long is the red ribbon?
  1. "6 cm longer" means the blue length plus 6 more.
  2. $18 + 6 = 24$.

Answer: 24 cm

Worked example: Find the smaller amount

A dog weighs 45 pounds. That is 5 times as much as a cat. How much does the cat weigh?
  1. 45 is 5 copies of the cat's weight.
  2. Split 45 into 5 equal parts: $45 \div 5 = 9$.
  3. Check: $5 \times 9 = 45$.

Answer: 9 pounds

Common mistake

Grabbing the numbers and multiplying no matter what the story says. Read the comparison words first: "more" or "less" means add or subtract; "times as" means multiply or divide.

Practice

Pass with 3 right answers, the last 2 in a row. Each right answer earns 2 XP.

Loading practice…

Builds on

Leads to

This is one of the top rungs of Grade 4.

Sources and further reading

  • Common Core State Standards for Mathematics, Grade 4, 4.OA.A.2 (multiply or divide to solve word problems involving multiplicative comparison)
  • OpenStax Prealgebra 2e, section 1.4 Multiply Whole Numbers
@teddyrookbook GitHub