Unit rates and more about proportions - 7th grade math
A unit rate is a rate where the second term in the rate is 1 of something, such as $5 per $1 or 65 miles : 1 hour. You can always solve the unit rate from a non-unit rate by dividing. For example, if you have the rate $46 per 6.5 hours, divide $46 by 6.5 to get the rate per 1 hour.
I solve word problems involving unit rates, and also show how unit rate relates to SLOPE in a linear equation. Basically, slope gives you the unit rate!
See also
How to find the unit rate, including with fractions
Math Mammoth Grade 7 curriculum (pre-algebra)