Law of subtraction and association: a number subtracts two numbers continuously, and the last two numbers can be added first and then subtracted.
The essence of subtraction: subtracting a number is equal to adding the reciprocal of this number. A-b=a+(-b). Subtracting one number and adding another number equals subtracting the difference between the two numbers. a-b+c=a+(c-b).
Add and subtract full algorithm: If two numbers are complementary to each other, multiply the largest number by 2, and then subtract its full number to get the answer. Direct subtraction of difference: if the last few digits of the minuend are not reduced enough, you can first decompose the minuend into the same number as the last few digits of the minuend and another number, and then subtract these two numbers again to get the result.
Solution of the difference: If you find the difference between a number and its last N digits, when the subtrahend is N digits and its last N digits are very large, then this difference is equal to: after the number smaller than the number before the last N digits, write down twice the last N digits of the subtrahend, and if it is less than N digits, add 0 before it.
Subtraction, union and addition: When doing the formula force of successive subtraction, firstly, they are complementary or the sum of two numbers is integer ten, integer hundred, integer thousand, etc. , and then add them together, and then subtract the sum of each group from the minuend in turn, which is the difference.
By the method of supplementing one with one, if the subtree is n bits and greater than the last m bits of the subtree, the sum of the subtree's complements can be obtained by subtracting one from the number before the last n bits of the subtree and keeping the rest bits unchanged.