Number & Operations for Teachers 

Copyright David & Cynthia Thomas, 2009

Exercises

1. Sketch area models for the following operations and compute their sums and differences. Clearly label the connections between the models and the algorithms.

a. 0.54 + 0.15

b. 0.76 – 0.23

c. 0.27 + 0.94

d. 1.25 – 0.65

2. Complete the following figure and write a question illustrating each of the six indicated connections. Note: The entire bar is 20 units in length and the shaded portion is 6 units in length

1. Complete the following figure and write a question illustrating each of the six indicated connections

2. Create a concept card for

a. Decimal addition

b. Decimal subtraction