Addition and Subtraction Expressions and Equations

An expression is a math statement with numbers and symbols. For example: 5 – y.
In expression 5 – y, y is a variable and 5 is a constant

To find the value of an expression, put the value of the variable in the expression and solve the expression

An equation is a mathematical statement with an equal sign

Equations can be solved by modeling them using plates and counters

Use counters to show the first number in the equation. Use an empty plate to represent the variable

Put total number of counters to the right of the plate. An equal sign shows that both sides name the same amount

Put counters on the plate so that the number of counters on each side of the equal sign is the same

An equation is a mathematical statement with an equal sign

Equations can be solved by modeling them using plates and counters

Equations can be solved just like arithmetic problems that have a missing addend – we subtract or add to find the missing number