SME
Grade 5 Math · Problem type
Compare measurements in different units
Use this for “Which is longer, 2.5 feet or 28 inches? By how much?”
Diagram
In the smaller unit, one is 2 more than the other.
This is an example. Type your own values to start a new problem.
First, in bigger unit
example
Smaller units in 1 bigger unit
example
First, in smaller unit
worked out (not typed)
Second, in smaller unit
example
How much more
calculated
Formulas
2.5 × 12 = 30
First, in bigger unit × smaller units in 1 bigger unit = first, in smaller unit
30 and 28 are 2 apart
Difference between the two measurements, in the smaller unit = how much more
Assumptions
•
To compare, put both measurements in the same unit. Change the bigger unit to the smaller one.
•
Then compare the two amounts and find the difference, in the smaller unit.
•
1 foot = 12 inches, 1 pound = 16 ounces, 1 gallon = 4 quarts, 1 meter = 100 centimeters, 1 kilometer = 1,000 meters. The bigger amount is in quarters (2.25, 2.5), so the smaller one is whole.
Step-by-step
WE KNOW
First, in bigger unit: 2.5
Smaller units in 1 bigger unit: 12
Second, in smaller unit: 28
FIND
first, in smaller unit, how much more
Step 1 · Find first, in smaller unit
2.5 × 12 = ?
First, in bigger unit × smaller units in 1 bigger unit = first, in smaller unit
Change the first measurement to the smaller unit: multiply.
First, in smaller unit = 30
Step 2 · Find how much more
30 − 28 = ?
Difference between the two measurements, in the smaller unit = how much more
Both are in the smaller unit now. Take the smaller amount from the bigger one.
How much more = 2 (the first measurement is more)
Check
Put the numbers back in. Both sides should match.
2.5 × 12 = 30 ✓
30 − 28 = 2 ✓
← Previous lesson
Convert units of measure with decimals
Next lesson →
Solve multi-step problems with units
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.