The method of continuous subtraction in senior one mathematics: carry addition calculation method.

Both two digits plus one digit and two digits plus two digits are applicable, and the most basic principle is the addition principle within 20. The fast formula of carry addition within 20 is: several +9, 1 minus1; A few +8, into 1 minus 2; A few +7, into 1 minus 3; A few +6, into 1 minus 4; A few +5, into 1 minus 5; A few +4, into 1 minus 6; A few +3, into 1 minus 7; A few +2, into 1 minus 8; A few+1 becomes 1 minus 9.

Calculation method of abdication subtraction. The fast formula of abdication subtraction is: several -9, ten times+1; A few -8, ten+2; A few -7, ten+3; A few -6, ten+4; A few -5, back ten+5; A few -4, ten+6; A few -3, ten+7; Several -2, ten+8; A few-1, ten +9. Because the positions of subtree and subtree in subtraction cannot be interchanged, in subtraction, two digits are observed first. When the subtree is larger than the single digits of the subtree, the answer can be calculated quickly by selecting the formula according to each digit of the subtree.

Subtraction:

Subtraction is a basic arithmetic operation. The operation of subtracting one quantity from another is called subtraction, and the result becomes difference. Given the sum of two addends and one of them, the operation of finding the other addend is called subtraction. The symbol of subtraction is "-",which is pronounced as negative sign. Used to calculate decrement!

Subtraction is not necessarily difficult, is it? Simple calculation. This method is suitable for preschool and first-grade children. For example: 24-8= 16, you can think of it this way: borrow 14-8, first use 10-8=2, then use 2+4=6, the difference must be 6, and the calculation is simple. That is to say, after borrowing a seat, first reduce the removed digits, and then add the reduced digits to the reduced digits, so that ten digits are not difficult.