Unit 4 Contents

18. Here is another problem that Tanya did using the compact method. The products that are added together in the compact method are called partial products. The final product is the sum of all the partial products.

1. Why did Tanya put a 3 above the problem?
2. How did Tanya get a 9 in the tens column of the first partial product?
3. How did Tanya get the 4 in the tens column and the 0 in the ones column of the second partial product?
4. Why did Tanya put a 5 above the problem?
5. How did Tanya get a 9 in the hundreds column in the second partial product?

Check-In: Question 19

19. Find the following products. Solve two of them using Frank's combination method and two of them using Tanya's compact method. Estimate the products to make sure your answers are reasonable.
1. 42  282
2. 19  11
3. 
4. 
5. How could you use estimation to make sure your answer to Question 19C is reasonable?

Use the Multidigit Multiplication Strategies Menu in the Reference section.

1. Solve each problem using any method you choose. Then solve it a second way. Estimate to check if your answers are reasonable.
1. 
2. 
3. 
4. 
2. Show or tell how you know your answer to Question 1D is reasonable.
3. Choose a problem in Question 1 and show or tell how to solve it using a mental math strategy.