First of all, there are about 70 to 100 eggs in the food store. If you use a row of five egg plates, it is just finished; If you use a row of six egg trays, it's just finished. How many eggs are there in this batch?

The answer is a multiple of 5*6=30, so it is 90.

2. Mom bought some wool, and it took 7/9 to knit a sweater for Dad and 1/27 to knit gloves for Xiaoyu. How much is left?

1-2/9- 1/27=20/27

A car travels 6 kilometers in 8 minutes. How many kilometers per minute do you drive on average?

6/8=0.75, and the average speed is 0.75km per minute.

4. The length and width of rectangular glass container are 3dm and1μ m.. Pour in 6.5L of water first, and then put in four identical apples. The water in the container is just full. How big is each apple?

(3 * 3 *1-6.5) = (9-6.5)/4 = 2.5/4 = 0.625 The volume of each apple is 0.625 liter.

Five, a math exam, the number of people who passed accounted for nine tenths, and five people were known to be unqualified. How many people are there in this class?

5/( 1-9/ 10)=50 There are 50 people in this class.

Six, a reservoir has 50 cubic meters of water, and about five-seventh of the water is polluted. How many cubic meters of polluted water is there?

50*5/7=35.7 1 The polluted water is about 35.438+0 cubic meters.