1000 minus two digits is aligned with the same digit. In terms of single digits, single digits are not enough. Borrow 1 from the tenth place, borrow from the hundredth place if there is no place, put it in the hundredth place as ten, then borrow 1 from the hundredth place, put it in the tenth place as ten, and put it in the tenth place as ten.

Integer subtraction in primary school mathematics first requires number alignment. If you subtract from the single digits, the single digits are not enough to borrow from the tenth digit 1, borrow 1 make 10, plus the base minus 1000-599. When calculating, we can see that the hundreds of digits that are reduced are all zero.

Introduction to subtraction

Subtraction is a mathematical operation that represents the operation of removing an object from a collection. Its symbol is the minus sign. For example, in the picture on the right, subtraction is to remove or reduce physical quantities and abstract quantities with different objects including negative numbers, fractions, irrational numbers, vectors, decimals, functions and matrices.

Subtraction follows several important patterns. It is anti-commutative, which means that changing the order will change the sign of the answer. It is not associative law, that is, when a subtraction exceeds two numbers, the order of subtraction is very important.

Subtracting 0 does not change a number. Subtraction also follows predictable rules related to addition and multiplication. These laws can be proved, starting with the subtraction of integers and summarizing them with real numbers and other things. Continue the general binary operation of these patterns and learn in abstract algebra.