Identify the problem type
1. Yesterday Aaron found some fossils. Today, he found 5 more fossils. In all, he found 13 fossils. How many fossils did he find yesterday?
JSU--more fossils now than before. Unknown is amount before he found more (start).
2. Nora has 9 red pens and 6 blue pens. How many more red pens than blue pens does Nora have?
CDU--no change over time. Comparison to find how many more of given amounts.
3. Peter had 10 video games. He gave some video games to Ethan. Now he has 2 video games left. How many video games did he give to Ethan?
SCU--fewer video games at the end than before (action is giving away). Unknown is amount given (change)
4. There are 14 bouncy balls in the toy box. 8 of the bouncy balls are green and the rest are blue. How many of the bouncy balls are blue?
PPW-PU--no change over time. A larger group is decomposed into two smaller groups. A smaller group amount (part) is the unknown.
5. Clara's uncle gave her 4 joke books when he visited. Now she has 7 joke books. How many joke books did she have before her uncle visited?
JSU--Change over time (getting more). More at the end than at the beginning (Join), unknown is the amount before (start).
6. Jane had some carrot sticks. She ate 2 carrot sticks. Now she has 1 carrot stick left. How many carrot sticks did she have before she ate any of them?
SSU--Change over time (eating some). Less at the end than the beginning (Separate). Unknown is the amount before (start).
7. There are 10 crystal rocks in the collection, and 7 polished rocks in the collection. How many rocks are in the collection?
PPW-WU--No change over time. Two smaller sets are being thought of as a larger set (part-part-whole). The larger set is the unknown (whole).
8. Joe gave 4 bouncy balls to Zach. Now Joe has 10 left. How many bouncy balls did he have to begin with?
SSU--Change over time (giving away). Less at the end than at the beginning (separate). The unknown is the amount at the beginning (start).
9. What is the most important related problem type for solving JSU problems?
PPW-PU
10. What is the most important related problem type for solving SSU problems?
PPW-WU
11. Besides the ones in problem 9 and 10, list two different ways that a child might solve a start unknown problem.