=( 10+4)× 12 1+(56× 16)÷56

= 10× 12 1+4× 12 1+ 16

= 12 10+484+ 16

= 17 10

Simple calculation of common laws is one of the important contents in mathematics, and it is also an important basis for students to learn mathematics and other disciplines. Simple calculation occupies a considerable part in primary school calculation problems, and it is also a knowledge point that students are easy to confuse and make mistakes.

Before the textbook is revised, it will be explicitly required to calculate the question types in a simple way. Some problems are not obvious at a glance, and students may try their best to find simple methods. After the revision of the textbook, simple calculation is integrated into calculation questions, which requires simple calculation with simple methods, which puts forward a new test for students. Some problems can't be worked out at a glance by simple methods, and students don't work out by simple methods. Even if the figures are correct, the teacher will give you a mistake.

The following are the simple operations of several algorithms that need to be mastered in primary school:

First, the law of additive association:

When three numbers are added, the first two numbers are added first and then the third number, or the last two numbers are added with the first number, and the sum remains unchanged. Expressed in letters: (a+b)+c=a+(b+c)

Second, additive commutative law:

When two numbers are added, the positions of the addend are exchanged and the sum is unchanged. Expressed in letters: A+B A+B+C = A+C+B C+B.

Integer: 42+36+58 If you look at this question, you will find that 42 and 58 can make up a whole hundred. According to the operation order, 42 and 36 should be counted first, so 58 and 36 can be exchanged, or 42 and 36 can be written as 42+58+36 or 36+(42+58).

Third, the law of multiplication and association:

Multiply three numbers, the first two numbers are multiplied and then the third number is multiplied, or the last two numbers are multiplied and then the first number is multiplied, and the product remains the same. Use letters to represent (a×b)×c=a×(b×c)

Integer: 47×25×4, 25 and 4 are good friends in multiplication, and 125 and 8 are good friends. The product of their multiplication is an integer, so whenever you see 25 and 125 in multiplication, you will associate them with 4 and 8. It can be written as 47×(25×4)

Fourthly, the multiplicative commutative law:

Multiply two numbers, exchange the position of the multiplier, and the product remains the same. Expressed in letters: a× b = b× a.

Integer: 25×37×4 Because 4 and 25 are combined and multiplied to get an integer, 37 and 4 can be interchanged, or 25 and 37 can be interchanged and can be written as 25×4×37 or 37×(25×4).

Five, the law of multiplication and distribution:

Multiplying the same number by the sum of two numbers is equivalent to multiplying the two addends by this number respectively, and then adding the two products, and the result remains the same. Use letters to represent a×(b+c)=ab+ac.

Although this is the only law, there are many changes in multiplication and division, and all the changes are inseparable from the fundamental principle of a×(b+c)=ab+ac. It is very important to understand and master its changes.