Use the display of the Rule Machine Master with
"Add 4" for the rule. See Materials Preparation and
Figure 3. Give students time to decide what goes in
the Output column and Number Sentence column.
After a few output numbers have been filled in, ask:
- Do you see a pattern in the Input column?
Describe the pattern. (All the numbers in the
input end in 0 or 9.)
- Do you see a pattern in the Output column? What
is the pattern? (All the numbers in the output end
in 4 or 3.)
- What would be the output for 39? How can you
use the pattern? (Possible response: 43; When we
add 4 to a number that ends with 9, the output
number always ends with 3.)
- What would be the output for 40? How can you
use the pattern? (Possible response: 44; When
you add 4 to a number that ends with 0, the output
number always ends with 4.)
- What addition fact helps you solve the outputs for
this Rule Machine? (9 + 4 = 13, 0 + 4 = 4)
- What would be the outputs for 50? 59? 60? 69?
(54, 63, 64, 73)
