Sums And Products - Sharp EL-531RH Teachers Manual

Sums and Products

• • • • • • • • • • • • • • • • • • • • • Objective • • • • • • • • • • • • • • • • • • • • •
Calculate with decimals and understand the results.
Select suitable sequences of operations and methods of computation, including trial-and-improve-
ment methods, to solve problems involving integers and decimals.
• • • • • • • • • • • • • • • Explanation of the activity • • • • • • • • • • • • • •
Choose two numbers whose sum is 10.
Find out what the product of those two numbers would be.
Find the products of other pairs of numbers whose sum is 10.
Find out which number pair gives the largest possible product.
This activity helps to reinforce students' understanding of the mathematical terms 'sum' and 'prod-
uct' and develops trial-and-improvement methods.
• • • • • • • • • • • • • • • • • Using the calculator • • • • • • • • • • • • • • • • •
Calculator functions used: Addition, multiplication, subtraction, parentheses
Press the following buttons and then start operation.
Try to find the largest product of any two numbers whose sum is 10.
Example:
2 8
2 8
You can also calculate this as 2 x (10 - 2) = 16.
2
What two numbers give the largest product?
Try multiplying various combinations of numbers whose sum is 10.
Ans: 5 x 5 = 25
1 0 2
2+8=
2X8=
2X(10-2)=
12
Junior high school
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