All students should complete Check-In: Question 13 on the Use Addition and Subtraction Strategies pages in the Student Activity Book. Ask students to share how they decided who would win the game. Encourage students to share the strategies they used to make their decision.
Use these or similar prompts to guide this discussion:
- How does knowing about place value help you decide who will win this game? (Possible response: Even though both girls can make a top number in the four hundreds, the biggest number Tanya can make will be 413 while Jackie can make the number 432. Since 32 is 19 more than 13 there is no way Tanya could win because both of the bottom numbers will be in the 50s.)
- What is the problem that will give Tanya her largest difference? (413 − 52 = 361)
- What is the problem that will give Jackie her largest difference? (432 − 51 = 381)
- Is there any way that Tanya could win this game? (Possible response: If Jackie did not place the 4 in the hundreds place but Tanya did then Jackie would lose.)
- If you use the 5 digits that Jackie and Tanya were given can you suggest a problem that would give you the largest possible difference? (543 − 12 = 531)
- How did you decide in what order to put your numbers? (Possible response: I made the largest possible number for the top number and the smallest possible number for the bottom number.)
- How can you use these 5 digits to make a problem that would have the smallest possible sum? (123 − 54 = 69)
As time permits, pose additional problems similar to Question 13 and provide time for student discussion.
Use Check-In: Question 13 on the Use Addition and Subtraction Strategies pages in the Student Activity Book to assess students' abilities to use place value knowledge to add and subtract multidigit numbers [E1] and add and subtract multidigit numbers using more than one strategy [E3].
