Mike bought 5 new baseball trading cards to add to his collection. the ne
day his dog ate half of his collection. there are now only 31 cards left.
how many cards did mike start with ?

What is the missing step in this proof ?

Mrs. gehrke said cheddar weighs 16.8 pounds. he actually weighs 15.2 pounds. what is the percent error?

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%