Q: At the pet store, there are 7 puppies and 6 kittens for sale. Two puppies and three kittens are sold. How many pets remain at the store?
A: There are 7 + 6 = 13 pets. They sell 2 + 3 = 5 pets. After the sales, there are 13 - 5 = 8 pets. The answer is 8.

Q: Ben has $2000 for his business operations costs. He orders goods from his supplier and writes them a cheque for $600. His debtor pays him $800 from the purchases they had made on credit. Mr. Ben then decides to do equipment maintenance and spends $1200 on the whole operation. How much money is Mr. Ben remaining with?
A: When Mr. Ben writes the cheque, he remains with $2000 - $600 = $1400. His debtor pays him $800, increasing his operation capital to $1400 + $800 = $2200. He spends $1200, remaining $2200 - $1200 = $1000 for business operations cost after maintenance. The answer is 1000.

Q: A pet store owner had 12 birds, 9 puppies, 5 cats, and 15 spiders. Half the birds were sold and 3 puppies were adopted. Then, someone left the spider enclosure open and 7 of them went loose. How many animals does the pet store owner have left?
A:
There are 12 / 2 = 6 birds left. There are 9 - 3 = 6 puppies left. There are 15 - 7 = 8 spiders left. The pet store owner has 5 + 6 + 6 + 8 = 25 animals left. The answer is 25.