Clocks, Calendars and Elapsed Time
Lessons in this chapter
About Clocks, Calendars and Elapsed Time
Clock a Doodle Doo! takes 1st grade’s hours and half hours down to five-minute precision, and adds the hardest time question there is: how long did that take.
Read Time on Clocks and Read Time to the Nearest 5 Minute refine the reading. Five-minute precision needs the multiplication-by-five that this year's tables supply, since the 3 on the clock face has to be read as fifteen minutes rather than three.
Find Elapsed Time is the difficult lesson, because time does not work in tens. Working out the gap from 10:40 to 11:15 cannot be done by ordinary subtraction, since there are sixty minutes in an hour, and counting on to the next hour and then onwards is the method that actually works.
Read Calendar covers days, weeks and months, and the arithmetic of dates. Working out the date two weeks from today, or which day of the week a date falls on, is where the repeating seven-day cycle becomes something kids calculate with rather than just recite.
Read Time on Clocks, Read Time to the Nearest 5 Minute and Find Elapsed Time each open as a worksheet in the page, scored as you work through it. Elapsed time is the one that wants the most repetition, because it is subtraction on a scale that does not run in tens. Four lessons, free to try, with no login needed for your first 3.
Frequently asked questions
Reading time on a clock, then reading it to the nearest five minutes, then finding how much time has passed between two readings, and finally reading a calendar. Telling time to five minutes sits in Measurement and Data (2.MD). Elapsed time and calendar reading go beyond what the Common Core asks at 2nd grade; elapsed time is a 3rd grade target in 3.MD.
Reading an analogue clock to the nearest five minutes, working out elapsed time, and reading and using a calendar.
Because time is not base ten. From 10:40 to 11:15 is 35 minutes, but ordinary subtraction gives the wrong answer since an hour is 60 minutes, not 100.
Count on to the next whole hour, then onward to the finish, and add the two parts. From 10:40, it is 20 minutes to 11:00 and 15 more, so 35 minutes.
Because each number on the clock face is five minutes, so the 3 means fifteen. Counting by five round the dial is the five times table in use.
Reading a calendar, naming days and months in order, and working out dates a given number of days or weeks away.