At the beginning of the month, he had 21 boxes of pens with 13 pens in each box. At the end of the month, there were 45 pens left. How many pens did he give out over the month?

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.