1. A subtraction formula, the sum of the subtracted, the subtracted and the difference is 100, the difference is two-thirds of the subtracted, what are the subtracted, the subtracted and the difference? 2. Class 1 and class 2 of grade 6 donated 1200 yuan to the disaster area. Class 1 of grade 6 donated 180 yuan more than Class 2 of grade 6. How much did class 1 and class 2 of grade 6 donate?

1. A subtraction formula, the sum of the subtracted, the subtracted and the difference is 100, the difference is two-thirds of the subtracted, what are the subtracted, the subtracted and the difference? 2. Class 1 and class 2 of grade 6 donated 1200 yuan to the disaster area. Class 1 of grade 6 donated 180 yuan more than Class 2 of grade 6. How much did class 1 and class 2 of grade 6 donate?

1. Subtraction = 100 (2 / 3 + 1 + 2 / 3 + 1) = 100 (10 / 3) = 30;
Difference = 30 × (2 / 3) = 20;
The subtracted number = 30 + 20 = 50;
2. Class 6 and class 2 = (1200-180) △ 2 = 1020 △ 2 = 510 yuan;
Class 61 = 1200-510 = 690 yuan;

There is a subtraction formula, the subtracted plus the subtracted, plus their difference, the sum is 512, the subtraction is 125, what's the difference?

Subtracted = subtracted + difference
If the sum of the subtracted plus the subtracted plus their difference is 512, then the subtracted is 512 / 2 = 256
The difference is 256-125 = 131

How many three digit numbers can be made up of 10 numbers from 0 to 9 without repetition? (there should be a simple formula process)

Use ten numbers from 0 to 9 to form an addition vertical. The number is four digits, but it can't be repeated

342+756=1098
The number of a thousand must be one, and there must be no zero in the number of a hundred and two addends except the sum,