Dan bought 8 new baseball trading cards to add to his collection. The next day his dog ate half of h

Dan bought 8 new baseball trading cards to add to his collection. The next day his dog ate half of his collection. There are now only 30 cards left. How many cards did Dan start with?

Let the original collection count of cards be b.

So we have (b + 8)/2 = 30

Cross multiply:
b + 8 = 30 * 2
b + 8 = 60

Use the equation calculator
b = 52 cards