Prior knowledge.

Recall multiplication facts
Use the rounding and compensating strategy when multiplying whole numbers
Use the place value strategy to solve problems involving whole numbers

Background

in this activity students who can use place value and compensating with whole numbers learn to use these strategies when multiplying decimals.

Comments on the Exercises

Exercise 1
Asks students to solve a basic fact and then use compensating to solve a multiplication problem involving a one decimal place decimal.  For example, 3 x 5 = 15 so 3 x 4.9 = 14.7, 3 x 4.8 = 14.4, 3 x 5.1 = 15.3, 3 x 5.2 = 15.6

Exercise 2
Asks students to solve multiplication problems involving decimals by using compensating. For example 3 x 6.8 = (3 x 7 = 21) - (3 x 0.2) = 19.4

Exercise 3
Asks students to solve multiplication problems involving decimals by using place value strategies.  For example, 2 x 4.2 = 8.4.

Exercise 4
Asks students to solve multiplication problems involving decimals by using place value strategies but the problems involve adding the tenths to the whole number.  For example, 4 x 3.4 = 12 + 1.6 = 13.6.

Exercise 5
Asks students to solve multiplication problems involving decimals by choosing the most appropriate strategy.