Number & Operations for Teachers 

Copyright David & Cynthia Thomas, 2009

Exercises

1. When adding or subtracting two single-digit base five numbers, what is the

a. Largest sum possible

b. Smallest sum possible

c. Largest difference possible

d. Smallest difference possible

2. When adding or subtracting two single-digit base two numbers, what is the

a. Largest sum possible

b. Smallest sum possible

c. Largest difference possible

d. Smallest difference possible

3. Complete the following operations, in each case modeling the steps and indicating connections between the concept model and the expanded algorithm.

Concept Model	Expanded Algorithm
Base Five
Base Two

4. Find two base five numbers whose

a. Sum is 1000_five

b. Difference is 444_five

5. Find two base two numbers whose

a. Sum is 1000_two

b. Difference is 111_two

6. Write a set of word problems corresponding to an addition/subtraction fact family in

a. Base ten

b. Base five

c. Base two

7. Given any whole number written in base five, how do you know if it is a multiple of five?

8. Given any whole number written in base two, how do you know if it is a multiple of two?