Math problem: the original price of a coat is 240 yuan, and the seasonal discount is reduced to 80 yuan. How much lower is the price of this coat than the original price? Process! Online, etc One more question: There are 18 classes in grade 4, 5 and 6 of a school, with an average of 48 students in each class. The ratio of students in grade 3 is 4:2:3. How many people were there in 1956??????????????? The process...........

Math problem: the original price of a coat is 240 yuan, and the seasonal discount is reduced to 80 yuan. How much lower is the price of this coat than the original price? Process! Online, etc One more question: There are 18 classes in grade 4, 5 and 6 of a school, with an average of 48 students in each class. The ratio of students in grade 3 is 4:2:3. How many people were there in 1956??????????????? The process...........

The price of this coat is lower than the original price
（240-80）÷240
=160÷240
=2/3
=66.7%
Do not understand welcome to ask

The price of a commodity is 15% lower than that of last year. The current price is the same as the original price______ %．

1-15% = 85%; so the answer is: 85

a. B is two different numbers from 0 to 9, and AA * BB = ccdd, then what is C + D equal to?
I know the calculation process, but I don't understand one step. Please help me
11a*11b=1100c+11d
11a*11b=11*c0d
So far, I don't know how I got it
c+d=11

11a*11b=1100c+11d
==>11*A*B=100C+D=99C+C+D
Because to be equal, both sides of the equation must contain a factor of 11
And 99c contains, C + D must also contain 11 factors, of course, C + D can also be a multiple of 11, 22, 33, and so on, but C and D are between 0 and 9
So only C + D = 11 is reasonable, other unreasonable
So c + D = 11