The calculation power of decimal addition and subtraction

1.

1) To calculate decimal addition and subtraction, first align the decimal point of each number (that is, align the number on the same digit),

2), then calculate according to the rule of integer addition and subtraction, and finally align the decimal point on the horizontal line in the number

summary: when calculating the decimal addition and subtraction method, the decimal points should be aligned, that is, the digits should be aligned

For example, Xiao Fang bought some apples and oranges in the supermarket, which cost 8.6 yuan for apples and 6.2 yuan for oranges. How much did he spend? 8.6 yuan is 8.6 Jiao, 6.2 yuan is 6.2 Jiao, 8 yuan + 6 yuan is 14 yuan, 6 yuan + 2 jiao is 8 Jiao, that is 14 yuan

So 8.6 + 6.2 is 14.8. Therefore, the decimal addition in the column vertical calculation, to align each digit, that is, the decimal point alignment. The subtraction of decimals is the same

2. When I teach the calculation of decimal multiplication and division, I find that some students have difficulty in mastering the calculation method of decimal division; Some students make a lot of mistakes in the calculation of decimal multiplication and division, and the calculation accuracy is not very high. For primary school students to strengthen the teaching of calculation, effectively improve the accuracy of calculation is a very important aspect of primary school mathematics teaching. So what causes students to make mistakes? I think about my present teaching.

3.

Decimal addition rule:

(1) same digit alignment

(2) starting from the low position

(3) for its decimal point position, the decimal point on the point

(4) there is a 0 at the end of the number, and the 0 is usually removed

extended data:

decimal multiplication rule:

(1) decimal multiplication integer: decimal multiplication integer: decimal multiplication integer, first according to the calculation method of integer multiplication, and then look at the number of decimal places in the factor, count the number of decimal points from the right side of the proct. If there is a zero at the end of the decimal of the proct, remove the zero

(2) decimal multiplication: the calculation method of decimal multiplication: convert decimal multiplication into integer multiplication for calculation; If you look at the number of decimal places in the factor, you can count the decimal points from the right side of the proct. If the number of decimal places in the proct is not enough, you need to add 0; If there is a 0 at the end, remove the 0

4. First align the decimal point, and then calculate the decimal part, and the integer algorithm is the same. Then calculate the integral part, for example:
2.34
7.1
+
13.67
-
0.9
- ---
- - - ---
- - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

5. Calculation rules of decimal addition and subtraction:
1) to calculate decimal addition and subtraction, 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 integer addition and subtraction, and finally align the decimal points on the horizontal line in the number
(there is a 0 at the end of the decimal part of the number. Generally, the 0 should be removed.)

6. Hello, I'm very happy to answer for you.

first of all, the decimal point should be aligned.

integer is not easy to calculate as the addition and subtraction method of integer.

decimals, decimals, percentiles and thousandths can be aligned. If not, zero can be added.

calculate according to the addition and subtraction method of integer

7. In vertical calculation of decimal addition and subtraction, the decimal (decimal point) should be aligned, and then from the (last) place, the decimal point of the number should be aligned with (original decimal point of addition or subtraction). When the result is a decimal and there is a zero at the end of the decimal, it should be simplified according to the basic property of the decimal.

8.

(1) 42.56 + 3.124 = 45.684

(2) 81-30.75 = 50.25

(3) 15.6 × 0.237 = 15.837

(4) 148.2-25.62-24.38 = 98.2 & # 8194

54.52﹣0.74﹣0.26=3.52 

60.42+5.4+1.58+2.6=10 

75.9+28.65﹣16.57=17.98 &# 8194;

857.5﹣3.25﹣16.75=37.5 

96.02+3.6+1.98=11.6 

101.29+3.7+2.71+6.3=14 

(11) 3.07-0.38-1.62 = 1.07

some of the above questions can be calculated by simple method using addition exchange law. Here we will not explain one by one the addition and subtraction method of decimal and decimal. For beginners, vertical calculation is still needed. Decimal addition calculation is integer plus integer, decimal plus decimal, and the decimal part is one place up if it is enough for 1

extended data:

decimal is a special form of real number. All fractions can be expressed as decimals. The dot in a decimal is called the decimal point. It is the boundary between the integral part of a decimal and the decimal part. A decimal whose integer part is zero is called a pure decimal, and a decimal whose integer part is not zero is called a decimal

9. The decimal addition and subtraction method uses the vertical formula to calculate. The method is: whether adding or subtracting, the decimal points of two numbers and quotient should be aligned up and down, and then calculated according to the calculation method of integer addition and subtraction.

10. Hello, this classmate
the algorithm of decimal addition and subtraction is: first align the decimal point (that is, align the same number of digits) in the decimal addition and subtraction operation, then calculate according to the calculation method of integer addition and subtraction, and finally align the decimal point and add the decimal point in the result
the main thing is to align the decimal points, that is, the decimal points of two addends and three sums, or the decimal points of the subtracted and the subtracted and the difference
I hope I can help you
how to calculate the addition and subtraction method within
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