Addition and subtraction
For example: 4 (addend) +3 (addend) =7 (sum)
Given the sum of two addends and one of them, the operation of finding the other addend is called subtraction.
Subtraction is the inverse of addition.
In subtraction, the sum of two known addends is called minuend, the known addend is called subtraction, and the required addend is called difference.
For example: 7 (minuend) -3 (minuend) =4 (difference)
Multiplication and division
The simple operation of finding the sum of several identical addends is called multiplication.
For example: 3+3+3 = 12.
It can also be expressed by multiplication as:
3,3 (multiplicand) ×4 (multiplier) = 12 (product)
Note: the same addend in the above addition formula should be regarded as multiplicand in the multiplication formula; The number of the same addend in the addition formula is used as the multiplier in the multiplication formula; Addition is the sum, which is called product in multiplication formula.
In multiplication, multiplicand and multiplier are also called factors of product. For example, in 3×4= 12, 3 and 4 can also be called factors.
Given the product of two multipliers and one of them, the operation of finding the other multiplier is called division.
Multiplying a number by a decimal number is a few tenths, a few percent and a few thousandths of this number.
Basic arithmetic
Basic arithmetic
(1) Parenthesless Peer Operation
(Addition and subtraction is one level, multiplication and division is one level): the operation order is calculated from left to right.
Example 1
1374+5329-476
=6703-476
=6227
calculate
Method 1: Change the operation order.
1374+5329-476
= 1374-476+5329
=898+5329
=6227
Because 6227 and the original calculation are correct.
Method 2: Inverse operation.
6227+476-5329
=6703-5329
= 1374
Because 1374 is equal to the first number in the original question,
So the original problem is calculated correctly.
(2) There are no brackets for different levels of operations.
: multiply first, then divide, then add and subtract.
Example 2
3245+963÷3×5-26 15
=3245+32 1×5-26 15
=3245+ 1605-26 15
=4850-26 15
=2235
(3) Arithmetic operation with brackets:
Count what is in brackets first, then what is in brackets, and finally what is outside brackets.
Example 3
[(3246+963)÷3+ 1000]×5-26 15
=[4209÷3+ 1000]×5-26 15
=[ 1403+ 1000]×5-26 15
=2403×5-26 15
= 120 15-26 15
=9400