Partner Practice with Number Line Diagrams
Directions: Create a number line diagram for each word problem. Evaluate your work to determine if
you calculated the time efficiently.
1. Eric completed a few activities yesterday afternoon. First, Eric watched television for an hour.
After he watched television, he practiced his violin for 24 minutes, and then he practiced
basketball for 18 minutes. If Eric was finished with his afternoon activities by 4:35 p.m. what
time did he start?
2. The school picnic began at 12:00 p.m. The students ate for 35 minutes, played games for 23
minutes, and finally the students cleaned up for an hour and 15 minutes. The students were
allowed to leave the picnic after they helped clean up. What time were the students allowed to
leave the picnic?
Answer Key for: Partner Practice with Number Line Diagrams
Directions: Create a number line diagram for each word problem. Evaluate your work to determine if
you calculated the time efficiently.
1. Eric completed a few activities yesterday afternoon. First, Eric watched television for an hour.
After he watched television, he practiced his violin for 24 minutes, and then he practiced
basketball for 18 minutes. If Eric was finished with his afternoon activities by 4:35 p.m. what
time did he start?
*Eric started his activities at 2:53 p.m.
This is one example of subtracting the time efficiently. Students may come up with several variations.
This is a written explanation of how students can solve. Students should show their work on a number
line diagram.
I initially look for times that can be decomposed to be combined with other times to easily subtract the
numbers. I see that 18 can be decomposed into 11 minutes and 7 minutes. If we combine the 24
minutes with 11 minutes from basketball, then we have 35 minutes. We can easily subtract 35 minutes
from 4:35 p.m. and now our time is 4:00 p.m. Now we can easily subtract an hour from 4:00 p.m. and
now our time is 3:00 p.m. Since we decomposed the 18 minutes into 11 minutes we now have 7 minutes
left to subtract. 3:00 p.m. subtract 7 minutes is 2:53 p.m.
2:53 p.m.
-35 min.
-1 hour
-7 min.
3:00 p.m.
4:00 p.m.
4:35 p.m.
2. The school picnic began at 12:00 p.m. The students ate for 35 minutes, played games for 23
minutes, and finally the students cleaned up for an hour and 15 minutes. The students were
allowed to leave the picnic after they helped clean up. What time were the students allowed to
leave the picnic?
*The students are allowed to leave the picnic at 2:13 p.m.
This is one example of adding the time efficiently. Students may come up with several variations. This is
a written explanation of how students can solve. Students should show their work on a number line
diagram.
The school picnic starts at 12:00 p.m. which is easy to add a whole hour to. I notice that if I combine 35
minutes and 23 minutes I have a total of 58 minutes. If I borrow 2 minutes from the 1 hour and 15
minutes the students spent cleaning, I will have 60 minutes. Now the one hour and 15 minutes I
borrowed from is 1 hour and 13 minutes. I can easily add the 60 minutes I composed to 12:00 p.m. and
have 1:00 p.m. Then I can add the hour the students spent cleaning to 1:00 p.m. Now I have 2:00 p.m.
Lastly, I will add the remaining 13 minutes. The ending time is 2:13 p.m.
+60 min.
12:00 p.m.
+ 1 hour
1:00 p.m.
2:00 p.m.
+13 min.
2:13 p.m.