The easy way to 21 25 30x30?

The recursive equation calculates 21 25 30 30

Solution: Four rules of operation (calculated in order, multiplication and division first, then addition and subtraction, parentheses are counted first, and power is calculated first), that is, the off-form operation (recursive equality calculation) needs to be carried out under the premise of this principle. Problem solving process:

Extended Information Vertical Calculation - Calculation Process: First align the last digit of the two multipliers, then use the second multiplier respectively, multiply each digit by a multiplier from the last digit, and finally add up the calculated result to be the product, if the multiplier is a decimal place, it can be expanded by the corresponding multiplier first, and finally the product is reduced by the corresponding multiple;

Problem solving process: Step 1: 5 30 = 150

Step 2: 2 30 = 600

Step 3: 5 30 = 15000

Based on the above calculations, the sum is 15750

If you have any doubts, please ask and be satisfied.

21*25*30*30 simple calculation, the specific solution steps are as follows:

In the study of mathematics, the basic content includes: the understanding of numbers, the operation of numbers, the understanding and operation of graphs, and the application of logarithms, these parts, but from the first grade to the sixth grade, I have been learning one content, and throughout, that is, simple operations.

Extract the common factor.

This method actually uses the multiplicative distributive property to extract the same factor, and the remaining terms in the exam are often added and subtracted, and an integer will appear, so we should pay attention to the extraction of the same factor.

Borrow and borrow and borrow.

When using this method, you need to pay attention to observation and find patterns. Also pay attention to repay, there is borrowing and repaying, and it is not difficult to borrow again.

In exams, when you see something like or close to a very good integer, you often use the borrowing-borrowing method.

Splitting method. The splitting method is to split a number into several numbers for the convenience of calculation. This requires mastering some "good friends" such as: 2 and 5, 4 and 5, 2 and, 4 and, 8 and so on. Be careful not to change the size of the number in the split.

Splitting and multiplicative distributive laws.

This method requires a flexible grasp of the splitting method and the multiplication distributive law, as seen in the exam paper8. When approaching an integer, you should first consider splitting.

Utilize the number of benchmarks.

Find a compromised number in a series of numbers to represent the series of numbers, of course, remember that the number should not be selected too far from the series of numbers.

Solution: 666666666666 You can use the multiplication method to assign the lead of the legal bridge to 222222222222 3, multiply 3 with the good 333333333333 of Minqiao, and then use the splitting method to decompose the result 999999999999 to (10000000000000-1) and then multiply it with the 222222222222, and subtract their products after the widest pair. Calculation process.

222222222222x999999999999

This problem is a fourth-grade problem that can turn 99 into 100 1, so that you can use the multiplication distributive law to calculate the couple.