Exponential equations are of the form 𝑦 = 𝑎 × 𝑘\(^𝑥 \) where 𝑦 is the new value, 𝑎 is the starting value and 𝑘 is the decimal multiplier that describes the growth or decay.

Throw one hundred coins, remove all those that come up tails, place them in a pile, repeat—you've got yourself a hands-on model for radioactive decay. The piles graphically show the meaning of the ...