Unit 15: Measurement, Time, and Money
Converting between units, tracking elapsed time, and handling money down to the last coin of change.
5 topics · 20 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
Converting Between Units of Length
- Worked exampleFind how many inches are in 5 feet of ribbon.
- Common mistakeWhy isn't 2 yards a smaller distance than 5 feet just because 2 is smaller than 5?
- Going furtherWhat happens to the number of units you need if you measure the same wall in centimeters instead of meters?
Your turn1 of 2
Amara has 14 feet of ribbon for a craft project. How many inches is that?Converting Between Units of Weight and Capacity
- How it worksWalk me through converting 3 pounds of apples into ounces by multiplying by 16.
- Common mistakeWhy isn't 2 quarts of juice the same amount as 2 gallons just because the numbers match?
- Worked exampleFind how many cups are in 3 pints of milk.
- Going furtherWhat changes about the number of grams you need if the same weight is measured in kilograms instead?
- Ties togetherHow does converting pounds into ounces use the same multiplying idea as converting feet into inches?
Your turn1 of 2
A farm stand sells 11 pounds of apples. How many ounces is that (multiply by 16)?Elapsed Time
- How it worksWalk me through finding the elapsed time from 2:30 to 5:15 by counting up in chunks.
- How it worksWalk me through finding the elapsed time from 10:40 to 1:20 by jumping to the next whole hour first.
- Worked exampleFind how much time passes between 3:20 in the afternoon and 6:05 in the afternoon.
- Common mistakeWhy isn't the time from 2:45 to 3:15 found by subtracting 2:45 from 3:15 like a regular subtraction problem?
Your turn1 of 2
Sam's soccer practice starts at 4:42 in the afternoon and ends at 12:24. How many minutes does practice last?Making Change and Adding Money Amounts
- How it worksWalk me through making change from a 20 dollar bill for a purchase of 13 dollars and 40 cents by counting up.
- Worked exampleFind the total cost of a book that costs 8 dollars and 50 cents plus a pencil that costs 75 cents.
- Ties togetherHow does making change by counting up connect to finding elapsed time by counting up to the next hour?
Your turn1 of 2
Ravi buys a book for 11 dollars and 64 cents, and a pencil for 93 cents. What is the total cost?Converting Between Units of Time
- How it worksWalk me through converting 3 hours into minutes by multiplying by 60 instead of 100.
- Common mistakeWhy isn't 150 minutes the same amount of time as 1 hour and 50 minutes?
- Common mistakeWhy isn't half an hour written as 0.5 hours the same as 50 minutes?
- Worked exampleFind how many minutes are in 4 hours and 15 minutes altogether.
- Going furtherWhat happens to the number of seconds you need if you measure the same stretch of time in minutes instead?
Your turn1 of 2
A long car trip takes 14 hours. How many minutes is that?