Fern bought groceries that cost $
14.38
$14.38 . She paid the store clerk, Ping, with a
$
20
$20 bill. Ping makes change by saying:

2
2 pennies makes the total
$
14.40.
$14.40.
6
6 dimes makes it
$
15.00
$15.00 , and
6
6 dollars makes it
$
20
$20 .

Did the clerk make a mistake in giving Fern her change?

1. The clerk did make a mistake in giving the change, he paid 1 dollar extra. When he paid Fern 6 dollars after the total was $15.00, the total would become 21 dollars, not 20.

6a. Divide the amount of sugar needed to make a cookie by the total there is. Each batch needs 0.25 cups and there are 5.50 cups, 5.50/ 0.25 is the same as 5.50 * 4, since 0.25 is the reciprocal of 4. 5.5 * 4 = 22

I can make 22 batches of chocolate chip cookies.

6b. Same with 6a, it is 5.5/0.75. 0.75 is equal to 3/4 and the reciprocal is 4/3, so it is 5.5 * 4/3. 5/5 * 4 = 22, 22/3 = 7 1/3

I can make 7 1/3 batches of lemon cookies

*You can also use 22/3 for the answer to 6b if you want