How easy to calculate 4 5 times 20 minus 3 5 times 2?

1 The law of arithmetic and simple calculation.

Key Knowledge Induction (1) The Law of Addition and Subtraction 1The commutative law of addition is defined: two additions that exchange positions, and an invariant alphabet.

2.Associative law of addition.

Definition: Add the first two numbers first, or add the last two numbers first, and the sum is unchanged.

Note: The associative law of addition has a wide range of applications if the sum of two additions happens to be a whole.

10. Whole hundred, whole thousand, then you can use the commutative law of addition to swap the positions of the additions in the original formula, and then combine the two additions.

3.Nature of Subtraction Note: These are derived from the commutative and associative laws of addition. Subtraction properties: If two numbers are subtracted from one number in a row, then the positions of the next two minus numbers are interchangeable.

Subtraction property: If two numbers are subtracted from a number in a row, then it is equivalent to subtracting the sum of the next two numbers from this number.

4.Splitting and rounding method is easy to calculate Splitting method: When a number is slightly larger than a whole hundred or a whole thousand, we can split the number into the sum of whole hundreds, whole thousands and a smaller number, and then use it.

Integer: When a number is slightly smaller than a whole hundred or a whole thousand, we can write this number as a whole hundred or whole thousand number minus.

When you look at this kind of problem, you think that you can just make up 10 or 100.

Look at it separately: original =

This question is very simple;

It's easy enough!

Please continue to ask questions later!

A simple calculation of multiplying by 4 minus a finger?

Wei Nian Chun 5 + 5 * 4 + high core 400

Hello, this simple calculation is based on the associative and distributive properties of multiplication. Original = .

Summary. Subtract 8 to equal.

An easy way to multiply and subtract.

Can you explain it to me?

OK. Multiply it into 4.

Multiplying by 4 equals 10

Then multiply equals 8 in and want

Subtract 8 to equal.

It is equivalent to saying that there are four of them.

That is true. There are four in it, which is the idea, and then expressed as 4 times.

1. Decompose it into (, and then divide by dividing the quotient obtained by dividing it by 5.

2. The dividend and the divisor are divided at the same time, and the resulting number can be divided again.

Note: When performing simple operations (four operations), you should pay attention to the relationship between the operation symbols (multiplication, division, addition and subtraction) and the big, medium and minor parentheses. Do not skip the arithmetic to avoid arithmetic errors.

Since multiplying with 4 is an integer thing, and multiplying with 8 is the whole number of bridges, it can be split