To find how much longer one thing is than another, subtract the shorter length from the longer length. Both lengths must use the same unit.
You can count up instead of taking away. A rope of 63 cm and a ribbon of 28 cm: count up from 28 to 30 (2), then 30 to 63 (33). The difference is 35 cm. Always write the unit in your answer.
Worked example
A rope is 84 cm long. A string is 46 cm long. How much longer is the rope?
- Find the difference: 84 − 46.
- 84 − 40 = 44, then 44 − 6 = 38.
Answer:38 cm
Key words
- difference
- how much more one amount is than another
- unit
- what we measure in, like cm
- count up
- find a difference by counting on
Practise this
New questions every time.
Common Core-referenced: 2.MD.B.5