Sixth grade mathematics volume I exercise book page 34 question 4 people's Education Press

Sixth grade mathematics volume I exercise book page 34 question 4 people's Education Press

6 times 6 = 36 square centimeters 36 times 4 / 9 = 16 square centimeters

How to write the last question on page 6 (attached)
Question: Xiaohai's deposits in the first quarter totaled 2700 yuan, 250 yuan less in the first month than in the second, and 80 yuan more in the second month than in the third. How many yuan did his family deposit in each of the three months? I'm in urgent need

Suppose: if you deposit X Yuan in the second month, you deposit x-250 in the first month and x-80 in the third month
x+（x-250）+（x-80）=2700
The solution is x = 1010
So the first month is 1010-250 = 760
The third month is 1010-80 = 930

National Standard Edition Grade 6 Volume 2 teaching aid for famous mathematics teachers
The inner diameter of the water pipe is 2 cm, and the flow rate of water in the pipe is 8 cm per second. When I went to wash my hands, I forgot to turn off the tap. How much water was wasted in 5 minutes?
The sum of all the edges of a cuboid is 1.8 meters, and the ratio of length, width and height is 6:5:4?
Ask you smart prawns to help out, little girl thanks, lotus root on the line waiting for clams, quick

Volume of water wasted per second
3.14 × 1 × 8 = 25.12 cm3
Volume of water wasted in 5 minutes
5 × 60 × 25.12 = 7536 CC
There are 12 edges, so 6x + 5x + 4x = 1.8
x=0.12
So the length, width and height are 0.720.60.48 respectively
Anyway, the area of one of the surfaces is twice as large
So it's obviously 2 × 0.72 × 0.6 = 0.864 square meters

Here's the unfinished equation 123456789 = 99, inserting the plus and minus signs where appropriate

1 + 23 + 45 + 6 + 7 + 8 + 9 = 99, right?