Casio fx-55 User manual

Casio Fx 55 • 7
Name: Date:
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Copyright © by Casio Inc. All rights reserved.
The Smart Calculator
Exploring Patterns
Ho and Jane were working together on a math assignment. They were using a
calculator to find the products shown below. Jane noticed that the first factor of
each set of products was the same. She wondered if there was a way to use the
calculator to find the products without entering the first factor each time. Ho
said that he knew of a way to use the and the keys to tell the calculator
to remember the first factor and then use the factor again. Can you help Jane
figure out how Ho used these keys? Explain why your key sequence works.
Then use your key sequence to complete the assignment. Describe the pattern
you see in each problem.
1. 16 x1 = _________ 2. 1,089 x1 = _________
16 x10 = _________ 1,089 x2 = _________
16 x100 = _________ 1,089 x3 = _________
16 x1,000 = _________ 1,089 x4 = _________
3. 10,989 x9 = _________ 4. 9 x1,089 = _________
10,989 x8 = _________ 9 x10,989 = _________
10,989 x7 = _________ 9 x109,989 = _________
10,989 x6 = _________ 9 x1,099,989 = _________
5. 8 x9 = _________ 6. 15,873 x7 = _________
8 x99 = _________ 15,873 x14 = _________
8 x999 = _________ 15,873 x21 = _________
8 x9,999 = _________ 15,873 x28 = _________
Thinking Cap
ThinkingCap
Use the pattern you found in each problem to give the next two products. Use the calculator to check your
answers.

8 • Casio Fx 55
FOR THE TEACHER
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Copyright © by Casio Inc. All rights reserved.
The Smart Calculator
Exploring Patterns
Using theActivity:
Students discover how to use the and the keys to find products that form patterns.
• The key can be used to enter the first factor into the memory of the calculator.
• The key can be used to recall the first factor and to find other products.
Example For the first product in problem 1, 16
X
1 16. For the second product, X
10 = 160. Continue using a similar key sequence to find all of the products. Note: The
key should be used to clear the memory before a new first factor is entered.
Assessment Encourage students to check their final products to be sure they see a pattern.
Answers
See example for key sequence. l. 16; 160; 1,600; 16,000. The first two digits are 1 and 6. Each product has one
more 0 at the end than the previous product. 2. 1,089; 2,178; 3,267; 4,356. The first digits are the whole
numbers in order starting with 1, the second digits are whole numbers in order starting with 0, the third digits
are whole numbers starting at 8 and going backwards, and the last digits are whole numbers starting at 9 and
going backwards. 3. 98,901; 87,912; 76,923; 65,934. The first digits are whole numbers starting with 9 and
going backwards, the second digits are whole numbers starting with 8 and going backwards, the third digits are
all 9s, the fourth digits are whole numbers in order starting with 0, and the last digits are whole numbers in
order starting with 1. 4. 9,801; 98,901; 989,901; 9,899,901. The first digits are all 9s, the second digits are all
8s, the next to last digits are all 0s, and the last digits are all 1s. Each product has one more 9 after the 8 than
the previous product. 5. 72; 792; 7,992; 79,992. The first digits are all 7s and the last digits are all 2s. Each
product has one more 9 after the 7 than the previous product. 6. 111,111; 222,222; 333,333; 444,444. The first
product is all 1s, the second all 2s, the third all 3s, and the fourth all 4s.
Thinking Cap
As an extension, students continue the pattern they found in each problem. They can use the key
sequence they discovered to check their answers.
Topic: Number Patterns
Objective: To use the calculator to discover
and extend patterns.
NCTM Standards: Communication,
Patterns, and Functions