Number and Operations Session 1: What Is a Number System?

Session 1, Part A:
A Simpler Number System

In This Part: Addition in Units Digit Arithmetic | Inverse, Identity, and Closure
Multiplication in Units Digit Arithmetic | Multiplicative Inverse and Identity

Problem A8

Fill in the multiplication table below using units digit arithmetic. For example, in our regular system, 6 • 3 = 18. But in units digit arithmetic, we are only interested in the units digit, so in this system, 6 • 3 = 8.

•	0	1	2	3	4	5	6	7	8	9

0

1

2

3

4

5

6

7

8

9

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Problem A9

a.
What patterns do you observe among the numbers in your table?

b.
Why do you think these patterns occur?

Next > Part A (Continued): Multiplicative Inverse and Identity

Session 1: Index | Notes | Solutions | Video