Answer:
2323
Step-by-step explanation:
Mental math means to find a way to do this problem in your head without using paper, pencil or a calculator.
The question says there are 23 classes and each class is to collect 101 items.
The equation would be 23 x 101.
To do this in your head real quick, make the numbers easier to multiply.
Make the 101 items 100. That means you are telling each class to collect 1 less item or 23 less items total.
You can do this in your head real quick. 23 classes collecting 100 items is 2300 items.
You had each class collect 100 items instead of 101. That mean you didn't collect 23 items. So if you add those back in, you will get
2323 items.