Kiara plays the card game with Andrew. The integer chips below represent the number of points she has after the first round. Then she earns 7 points in
the second round.

a. How many points does Kiara have after the first round?
b. Draw chips to show the points Kiara earns in the second round.
Then circle the zero pairs or tell how many pairs there are.
c. How many points does Kiara have after the second round?
d. What is - 7 + 7?

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.