Elapsed time problems
Solve word problems involving elapsed time by adding and subtracting time intervals in minutes, including using a number line
What a learner can do afterwards
- A film starts at 2:15 and lasts 47 minutes. When does it end?
- Calculate how many minutes between 9:20 and 10:05
- Use a number line to show the elapsed time between two events
1 · Read
A number line can show time passing. Start at the beginning time, then hop forward by the number of minutes that pass. Wherever you land is the end time.
To add 47 minutes to 2:15, break the jump into friendly pieces. First hop 5 minutes to reach 2:20. Then hop 40 minutes to reach 3:00. A clock's minutes stop at 59, so that hop lands on 3:00 and never on 2:60. Then hop the last 2 minutes to land on 3:02.
To find the minutes between 9:20 and 10:05, hop forward from 9:20 to 10:00. That is 40 minutes. Then hop 5 more minutes to reach 10:05. So 40 minutes plus 5 minutes is 45 minutes in total.
When the jump is large, hop to a friendly number first, like the next ten or the next hour. Small hops are easier to count than one big jump.
Hop forward on a number line by the elapsed minutes, and friendly chunks make big jumps easy to count.
More to read
Telling time review
Elapsed time starts with reading both ends exactly. A film from 2:15 to 3:02 needs both times pinned before any subtracting. Misread one end and the gap goes wrong automatically. Read hour hands first, then minutes in fives plus ones. Then bridge through the next hour: 45 minutes to 3:00 plus 2 more is 47. Bridging splits one hard gap into two easy hops.
Converting units of time review (seconds, minutes, & hours)
Minutes between times come from hopping, not big subtraction. From 9:20 to 10:00 is 40 minutes, then 5 more to 10:05, totalling 45. The hour boundary is the natural rest stop. Jump to it first, then mop up the remainder. Number lines draw the hops as arrows. Label each arrow with its minutes and add the labels. Labelled arrows turn invisible time into visible distance.
How to Tell Time on a Clock: Easy Steps for Beginners
Clock basics power every elapsed problem. The short hand creeps between numbers while the long hand sprints round in 60 minutes. At 2:15 the long hand points at the 3 and the short hand leans past 2. Knowing 3 means 15 minutes unlocks start times fast. Sketch both clocks when stuck. Two drawn faces beat two imagined ones. Draw, label, then hop between them.
How to Read a Clock for Beginners (Analog and Digital)
Digital and analogue clocks tell the same story in different fonts. 3:02 digital matches a wall clock with hands pointing just past 3:00. Matching pairs trains flexible reading: 10:05 digital with hands near 10 and just past the 2. Fluency both ways speeds elapsed work. Read either clock on sight and the gap maths can begin.
Explore more
2 · Watch
به انگلیسیTake it off screen
Where it sits
This opens up
Nothing builds on it yet.
Where this leads
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.