The correct number is 108. The analysis unit copied 6 into 9, so I added 3. Hundreds of people copied 1 into 7, so they added 600. 7 1 1-3-600=708-600= 108。
Extended data
1. subtraction is the number subtracted from the minuend in the subtraction formula. In subtraction, for example, a-b=c, reading A minus B equals C, A is called the minuend, and B is called the minuend.
2. In the subtraction formula, the number before the minus sign is the minuend, the number after the minus sign is the minuend, and the number after the equal sign is the difference.
Subtraction is one of the four operations, and the operation of subtracting another number or quantity from one number or quantity is called subtraction. The minuend is the number that is subtracted. The mathematical method of subtracting one number or quantity from another can be summarized as m-s=r, where m is the minuend, s is the subtraction and r is the difference.
Evolution of formula: minuend = subtraction+difference; Subtraction = minuend-difference; Difference = minuend-minuend.
The significance of rational number subtraction;
The significance of rational number subtraction is the same as that of elementary school subtraction. When two numbers are known and one of them is added to find the other, it is called subtraction. Subtraction is the inverse of addition. In elementary school, the minuend was greater than the subtraction. After introducing negative numbers, any two numbers can be subtracted.
The subtraction rule of rational numbers:
1, the subtraction of rational numbers, the operation of subtracting large numbers from decimals can't be simplified directly as in primary schools, but converted into addition. The key is to correctly convert subtraction into addition, and then calculate according to the addition law and operation law of rational numbers.
2. When converting subtraction into addition, pay attention to two changes, namely, "First, subtraction becomes addition; The second is to turn the subtrahend into its reciprocal. "
3. When the rational number subtraction operation fails to be converted into addition operation, the positions of the minuend and the minuend cannot be interchanged, because there is no commutative law in subtraction.
Subtract any number from 0 to get the reciprocal of this number.