Understanding negative number addition and subtraction with variables | |
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Description | |
Exercise Name: | Understanding negative number addition and subtraction with variables |
Math Missions: | 7th grade (U.S.) Math Mission |
Types of Problems: | 3 |
The Understanding negative number addition and subtraction with variables exercise appears under the 7th grade (U.S.) Math Mission. This exercise uses the number line to provide understanding of operations of addition and subtraction on integers.
Types of Problems
There are three types of problems in this exercise:
- Select the statements that are true: This problem provides a number line diagram and four statements. The user is asked to select all of the statements that are true from the multiple select list.
- Select the correct relation: This problem provides two expressions and a diagram. The user is asked to select the correct symbol from among < , > and = to make the statement true.
- Describe how to move: This problem provides an arithmetic expression involving variables and negatives. Users are asked to describe how to interpret the expression on the number line.
Strategies
This exercise and knowledge of this topic can assist on many previous topics. Previous topics that refer to "number line" analysis of integers are specifically referring to this exercise (links to be provided).
- The diagram is not necessary on the Select the statements that are true problem. They can be done more quickly by reading the statements and determining their truth value without reference to the number line.
- The geometric interpretation of an opposite is to reflect over the origin at zero. This fact can help on the Select the correct relation problem.
- The answer to the Describe how to move problem will always begin with the "starting" at the initial number and then moving either left or right some number of units. Left is subtracting a positive, right is subtracting a negative (which is equivalent to addition).
Real-life Applications
- Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature.
- Negative numbers are used to represent land below sea level.