Different Products - Sharp EL-531RH Teachers Manual

Different Products

• • • • • • • • • • • • • • • • • • • • • Objective • • • • • • • • • • • • • • • • • • • • •
Estimate and approximate solutions to problems.
• • • • • • • • • • • • • • • Explanation of the activity • • • • • • • • • • • • • •
Have the class make up multiplication problems using the digits 1, 2, 3 and 4. Each digit can only be
used once. Find out what the largest product among the possible answers will be.
While working on this activity, students should practice their skills of mental estimation. They
should also be interpreting and generalizing their answers.
What is the largest number you can make by pressing the keys
once and only once?
Example:
12 34
2 341
Can you make a larger number?
Using algebra, for any four digits a, b, c, d, where
a < b < c < d, the largest product is given by:
(10d + a) x (10c + b).
Ans: The largest product is given by
41 32 32
10
Junior high school
and