A summary of the methods and skills of quick calculation in primary school mathematics

To do math problems quickly, you must master some quick calculation methods. I sorted out some quick calculation methods in primary schools. Let's have a look.

Signed movement method When a calculation problem has only one-level operation (only multiplication and division or only addition and subtraction) and no brackets, we can "sign movement".

a+b+c=a+c+b

a+b-c=a-c+b

a-b+c=a+c-b

a-b-c=a-c-b

In the simple calculation of addition and subtraction before rounding, the basic idea is "rounding" According to the properties of commutative law, associative law and addition (multiplication) subtraction, if any of them can be rounded, the formula can be changed, so that the rounded numbers form a pair of good friends and the rounding calculation can be simplified.

Use the benchmark number to find a more eclectic number in a series of numbers to represent this series of numbers. Of course, remember that the selection of this number should not deviate too far from this series.

For example: 2072+2052+2062+2042+2083 = (2062x5)+10-120+21=1031.

The above is some information about math problem-solving skills, I hope it will help you.