Mathematics
Grade 6
15 min
Add and subtract integers: input/output tables
Add and subtract integers: input/output tables
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1
Introduction & Learning Objectives
Learning Objectives
Define integers, positive integers, and negative integers.
Accurately add and subtract integers using various strategies.
Identify the 'input' and 'output' values in a mathematical table.
Apply a given rule to complete an input/output table involving integer addition or subtraction.
Determine the mathematical rule (addition or subtraction of an integer) that connects input and output values in a given table.
Explain their reasoning for determining rules and completing tables involving integer operations.
Ever wonder how meteorologists predict temperature changes, especially when it goes below zero? 🌡️ Or how a submarine's depth changes? These are all about adding and subtracting integers!
In this lesson, you'll dive into the...
2
Key Concepts & Vocabulary
TermDefinitionExample
IntegerA whole number (not a fraction or decimal) that can be positive, negative, or zero. Examples: -3, 0, 5.The numbers ..., -2, -1, 0, 1, 2, ... are all integers.
Positive IntegerAn integer greater than zero. It can be written with a '+' sign or no sign at all.5, 12, +7 are all positive integers.
Negative IntegerAn integer less than zero. It is always written with a '-' sign.-3, -10, -1 are all negative integers.
InputThe starting value in an input/output table, which is fed into a rule or operation.In a table where the rule is 'add 3', if the input is 2, then 2 is the input value.
OutputThe result or ending value after applying a rule or operation to the input.If the input is 2 and the rule is 'add 3', the output is 5. So,...
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Core Formulas
Adding Integers with the Same Sign
$$a + b = \text{sign}(a) \times (|a| + |b|)$$
If two integers have the same sign (both positive or both negative), add their absolute values and keep the original sign. For example, $3 + 5 = 8$ and $(-3) + (-5) = -8$.
Adding Integers with Different Signs
$$a + b = \text{sign of larger absolute value} \times (||a| - |b||)$$
If two integers have different signs (one positive, one negative), subtract their absolute values. The sum will have the sign of the integer with the larger absolute value. For example, $5 + (-3) = 2$ and $(-5) + 3 = -2$.
Subtracting Integers (Add the Opposite)
$$a - b = a + (-b)$$
To subtract an integer, change the subtraction sign to an addition sign and change the sign of the second integer to its opposite. The...
5 more steps in this tutorial
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Challenging
A student is filling out a table with the rule 'Subtract -8'. For an input of -10, they calculate the output as -18. What was their mistake?
A.They added the absolute values instead of subtracting them.
B.They subtracted 8 instead of adding 8.
C.They added -8 instead of subtracting -8.
D.They should have gotten a positive answer.
Challenging
The temperature at 6:00 AM is -11°F. The temperature changes according to the rule 'Add 4' every hour. What is the temperature at 9:00 AM?
A.-15°F
B.1°F
C.-7°F
D.-3°F
Challenging
First, determine the rule for the table. Then, find the missing output for an input of 0.
| Input | Output |
|---|---|
| 9 | -2 |
| 15 | 4 |
| 0 | ? |
A.9
B.11
C.-11
D.-9
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