Im being timed so uhh help please

Abox holds 500 paperclips. after a week on the teacher's desk 239 paperclips remained. how many paperclips were used?

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g

The interior angles formed by the sides of a hexagon have measures that sum to 720°. what is the measure of angle a? enter your answer in the box. m∠a= °