Level 13 Level 15
Level 14

## Ignore words

Check the boxes below to ignore/unignore words, then click save at the bottom. Ignored words will never appear in any learning session.

Ignore?
subtract 27
To "undo" add 27, I would...
subtract 4
To "undo" add 4, I would...
To "undo" subtract 65, I would...
To "undo" subtract 37, I would...
divide by 10
To "undo" multiply by 10, I would...
divide by 7
To "undo" multiply by 7, I would...
multiply by 9
To "undo" divide by 9, I would...
multiply by 23
to "undo" divide by 23, I would...
Equation
A mathematical sentence that contains an equals sign
Variable
an alphabetic character representing a number, called the value, which is either arbitrary or not fully specified or unknown. It is usually a letter like x or y.
equivalent
Equal to
inverse operation
Operations that undo each other
Subtraction
to take a quantity away from another
to join two or more quantities
Division
process of breaking a quantity into equal parts
Multiplication
inequality
A mathematical sentence that shows the relationship between quantities that are not equivalent
<
Less than
>
Greater than
Less than or equal to
Greater than or equal to
Not equal to
x+9-9
x+9
x-7+7
x-7
-7
What is the inverse of +7?
plus 15
What is the inverse of minus 15?
divide by 6
What is the inverse of times 6?
minus 4
What is the inverse of plus 4?
times 3
What is the inverse of divided by 3?
undoes the given operation
What does the inverse operation do?