Understanding Functions: Input and Output
Explore the basics of functions, identifying input, output, and rules with this Grade 5 math worksheet.
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Understanding Functions: Input and Output
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Read each question carefully and follow the instructions to complete the function tables and identify the rules.
A function machine takes an , applies a , and produces an .

In mathematics, a function is like a machine that takes a number (input), does something to it (rule), and gives you a new number (output).
For each function table, determine the rule that changes the input to the output. Write the rule in the form of an equation (e.g., Output = Input + 5).
1. Input: 2, Output: 4 Input: 5, Output: 7 Input: 8, Output: 10
Rule:
2. Input: 6, Output: 3 Input: 10, Output: 5 Input: 14, Output: 7
Rule:
Complete the following function tables based on the given rule.
3. Rule: Output = Input × 3
Input
Output
4
7
10
4. Rule: Output = Input - 9
Input
Output
15
20
25
5. If the rule is 'Output = Input + 12', what is the output when the input is 7?
5
19
12
7
6. If the output is 28 and the rule is 'Output = Input × 4', what was the input?
7
24
32
4
7. In a function, for every input, there is only one possible output.
True
False