How to use base ten blocks divided by 4.9 divided by 7

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

The dash figure is a dilation if the original figure. find the scale factor. classify the dilation as an enlargement or a reduction

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?