Why decimal points are aligned to add and subtract

When calculating addition and subtraction, the same counting unit is required to add and subtract. In integers, from the right, the first digit is a single digit, the second digit is ten, and the third digit is a hundred......Therefore, in the vertical formula of calculating integer addition and subtraction, as long as the last digit is aligned, the same digits are aligned, and the same counting units can be added and subtracted.

This was invented by ancient Greek mathematicians and evolved by later generations to maximize the accuracy and speed of calculations...

Because if it is not aligned, the number of digits will be wrong, resulting in an incorrect result for e.g. the alignment of the single digit and the ten digits.

Because numbers are divided into integer parts and decimal parts, of course, the integer part corresponds to the decimal part, otherwise the integer part and the decimal part lose their due meaning. The decimal part is because it's not enough to round 1, and if it's enough, it goes in.

Before and after the decimal point are integers and decimals, they can be aligned to reduce integers and decimals, otherwise it is easy to make mistakes.

1.The decimal point is preceded by an integer place, and the decimal place is followed by a decimal place; 2.According to the algorithm of addition and subtraction, integer digits are aligned to integers, and decimal places are aligned to decimal places. If you add or subtract without aligning the decimal point, the units will be messed up and the calculated result will be wrong!

In this way, it can be counted one by one

The addition and subtraction of decimal numbers has the same requirements as the addition and subtraction of integers: the numbers of the same unit can be added and subtracted, that is, the same nanometer or digits must be aligned.

When calculating the addition and subtraction of integers, as long as the last digit is aligned, that is, the single digit, the other digits are also aligned.

1. The last place of the decimal place is not fixed, and the last place of a decimal place may be the percentile.

If its last digit is in the percentile, which means 5 hundredths), it may also be in the thousandth place, if the last digit of this decimal place is in the thousandth place, it means 5 thousandths).

2. If you add the last digits of these two decimal places, it is obviously not possible because their digits are not the same. If you align them to decimal places, the same digits will also be aligned, and the addition and subtraction of decimal places can be performed correctly.

3. From the vertical calculation, you can also see why the decimal points should be aligned. As can be seen from the vertical type, the decimal point is aligned, the ten digits are aligned with the tens, the single digits and the single digits, etc., that is, the same digits are aligned.

4. Why should the decimal point be aligned, because to ensure accuracy and accuracy, if the decimal point is not aligned with the answer, then for a string of numbers, there may be a kaleidoscopic result, then the outcome is very different, sometimes it will lead to a big mistake.

<> decimal addition and subtraction decimal point should be aligned because the decimal point is preceded by an integer digit and followed by a decimal place.

There are four issues to pay attention to in multiplication vertical calculation:

1. The last digit of the two numbers should be aligned.

2. Try to write the numbers with more numbers on the top and the numbers with fewer numbers below to reduce the number of multiplications.

3. If there is a chaotic "0" at the end of the two numbers, you can only align the last digit of the number in front of the "0" when writing the vertical type, and finally add the number of acres of "0" common to the two numbers behind the vertical product.

4. Decimal multiplication should determine the position of the decimal point of the product according to the multiple of the decimal place.

When calculating decimal addition and subtraction, pay attention to aligning the decimal points. That's right.

Calculation rules for decimal addition and subtraction:

1) Calculate the addition and subtraction of decimals, first align the decimal points of each number (that is, align the numbers on the same digit), 2) then calculate according to the rules of addition and subtraction of integer numbers, and finally align the decimal point on the horizontal line in the obtained number.

There is a 0 at the end of the decimal part of the number, and the 0 should be removed in general. ）

When calculating decimal addition and subtraction, align the decimal points, which means align the digits! Hope it helps you and I wish you happiness.

The decimal point of decimal addition and subtraction should be aligned because the decimal point is preceded by an integer place, followed by a decimal place, and the addition and subtraction of the alignment can ensure that each number is added or subtracted from the same digit, rather than the number of other digits, so that it is not easy to miscalculate.

There are four issues to pay attention to in multiplication vertical calculation:

1. The last digit of the two numbers should be aligned.

2. Try to write the number with more numbers on the top, and the number with fewer numbers on the roll core to reduce the number of multiplications. Alternate liter.

3. If there is a "0" at the end of the two numbers, you can only align the last digit of the number before the "0" when writing the vertical type, and finally add the number of "0" common to the two numbers after the vertical product.

4. Decimal multiplication should determine the position of the decimal point of the product according to the multiple of the decimal place.