Time and Elapsed Time
Lessons in this chapter
About Time and Elapsed Time
Time in 3rd grade takes clock reading to minute precision and then spends the rest of the chapter on the question kids find hardest: how long did that take.
Read and Write Time to the Nearest Minute removes the five-minute scaffold 2nd grade used. Every mark on the dial now counts, which means counting on from the nearest numeral rather than reading the numeral itself, and writing the time correctly in both the 3:47 and the “thirteen minutes to four” forms.
Solve Problems on Elapsed Time is the substantial lesson. Elapsed time resists ordinary subtraction because an hour has sixty minutes, not a hundred, so the reliable method is counting on: from 10:40, twenty minutes to eleven, then fifteen more, giving thirty-five.
A number line is the tool that makes this visible, with the hour boundaries marked as jumping-off points. It is the same counting-on strategy from 1st grade applied to a scale that is not base ten, which is why it needs its own lesson rather than being treated as subtraction.
Read and Write Time to the Nearest Minute and Solve Problems on Elapsed Time are the chapter's two lessons, each a worksheet worked in the page and marked as your child answers. Elapsed time is the one that needs the repetition, because it is subtraction on a scale that runs in sixties rather than tens. Both are free.
Frequently asked questions
Reading and writing time to the nearest minute, which is a step up from the five-minute reading done in 2nd grade, and then solving problems about how much time has passed. Two lessons, and almost all of the difficulty is in the second. It sits in Measurement and Data (3.MD).
Reading and writing time to the nearest minute, and working out elapsed time between two times, including across an hour boundary.
Because time is not base ten. 11:15 minus 10:40 by ordinary subtraction gives 75, but the answer is 35 minutes, since an hour is 60 minutes.
Count on to the next whole hour, then onward to the finish, and add the parts. From 10:40 that is 20 minutes to 11:00 plus 15 more, so 35 minutes.
Every mark counts, so a child has to count on from the nearest numeral rather than just multiplying it by five. It is noticeably harder.
Yes. Marking the start, the hour boundaries and the end makes the jumps visible, and it is the method that keeps working for longer intervals.