The ten coins in the first volume of mathematics in the fifth grade of the Primary School Learning and Practice Park are composed of 20 yuan and 50 yuan, with a total value of 4 10 yuan. How many RMB sheets are there? If you use arithmetic instead of equations,

50 yuan has: (410-20x10)/(50-20) = 7 (sheets).

20 yuan has: 10-7=3.

Analysis: Assume that 10 is from 20 yuan, and the total number is 20x10 = 200.

Actually, 4 10 is 4 10-200=2 10, which is more than 200 yuan.

And more than 50 to 20 is 50-20 = 30 yuan.

So the number of 50 sheets is 2 10/30=7 (sheets).