We have a question: Sixteen boys and 14 girls attended Simon's birthday party. Three-fourths of the boys and 6/7 of the girls brought gifts. How many of those who attended did not bring gifts?
And an answer: 6
So how you got the answer?
16 x 3 / 4 = 12 boys brought gifts. So, 16 - 12 = 4 boys did not bring gifts. 14 x 6 / 7 = 12 girls brought gifts. So, 14 - 12 = 2 girls did not bring gifts. Therefore, a total of 4 boys + 2 girls = 6 people did not bring gifts.

We have a question: Jen bought a bag of cookies and ate three-quarters of the bag that day. The next day, she ate half of the remaining cookies. She has 8 cookies left on the third day. How many cookies were in the bag to start?
And an answer: 64
So how you got the answer?
On the third day, Jen had half of the second day’s cookies left, so on the second day, she had 8 * 2 = 16 cookies. On the second day, she had 1 / 4 of the first day’s cookies left, so she started with 16 * 4 = 64 cookies in the bag.

We have a question: Sam memorized six more digits of pi than Carlos memorized. Mina memorized six times as many digits of pi as Carlos memorized. If Mina memorized 24 digits of pi, how many digits did Sam memorize?
And an answer: 10
So how you got the answer?
Carlos memorized 24 / 6 = 4 digits of pi. Sam memorized 4 + 6 = 10 digits of pi.