Fifth grade volume I decimal division algorithm
Publish: 2021-04-24 04:20:59
1. When doing decimal division, pay attention to some common sense problems
1. Divisor and divisor cannot be zero. If there is, the number obtained will be zero directly
2. When the divisor is a decimal, expand the corresponding multiple to make the number an integer, but the divisor should also expand the corresponding multiple
case 2.3 ÷ 23, 0.23 is expanded 100 times to 23, but the divisor is also expanded 100 times to 230, so the algorithm of the original formula in the draft becomes 230 ÷ 23 = 10, question 2.3 ÷ 23 = 10, which is the calculation method. Of course, if there is a remainder, the remainder should be written, which is the same as the division method of integers
the most important point of decimal point division calculation is to change the divisor into an integer. The divisor can also have a decimal, but the decimal point should be aligned
example: 2.3046 ÷ 23, 230.46 in draft calculation ÷ 23=10.02
1. Divisor and divisor cannot be zero. If there is, the number obtained will be zero directly
2. When the divisor is a decimal, expand the corresponding multiple to make the number an integer, but the divisor should also expand the corresponding multiple
case 2.3 ÷ 23, 0.23 is expanded 100 times to 23, but the divisor is also expanded 100 times to 230, so the algorithm of the original formula in the draft becomes 230 ÷ 23 = 10, question 2.3 ÷ 23 = 10, which is the calculation method. Of course, if there is a remainder, the remainder should be written, which is the same as the division method of integers
the most important point of decimal point division calculation is to change the divisor into an integer. The divisor can also have a decimal, but the decimal point should be aligned
example: 2.3046 ÷ 23, 230.46 in draft calculation ÷ 23=10.02
2. 3.71 * 3.1 5.2 * 6.2 OK, I'll send more
3. Analysis of vertical calculation example of decimal division 821 ÷ 23
solution idea: divide each digit of the divisor from the high position, keep the quotient of each calculation, and add the remainder to the next digit to calculate, so the divisor will be calculated in this order, so the quotient will be combined in order, and the remainder is the last operation result
solution process:
Step 1: 82 ÷ 23 = 3, the remainder is: 13
Step 2: 131 ÷ 23 = 5, the remainder is: 16
according to the above calculation steps, the combined result is 35, and the remainder is 16
checking calculation: 35 × 23 + 16 = 821
extended data → checking results: four operation rules (calculation in order, multiplication and division first, addition and subtraction second, brackets first, multiplication and square first) that is, disjunction operation (recursive equation calculation) should be carried out under the premise of this principle
problem solving process:
35 × 23 + 16
= 805 + 16
= 821
if in doubt, please ask, if satisfied, please adopt
solution idea: divide each digit of the divisor from the high position, keep the quotient of each calculation, and add the remainder to the next digit to calculate, so the divisor will be calculated in this order, so the quotient will be combined in order, and the remainder is the last operation result
solution process:
Step 1: 82 ÷ 23 = 3, the remainder is: 13
Step 2: 131 ÷ 23 = 5, the remainder is: 16
according to the above calculation steps, the combined result is 35, and the remainder is 16
checking calculation: 35 × 23 + 16 = 821
extended data → checking results: four operation rules (calculation in order, multiplication and division first, addition and subtraction second, brackets first, multiplication and square first) that is, disjunction operation (recursive equation calculation) should be carried out under the premise of this principle
problem solving process:
35 × 23 + 16
= 805 + 16
= 821
if in doubt, please ask, if satisfied, please adopt
4. Law of combination of multiplication: letter a × b × c=a ×( b × c) Example: 32 × 0.25=8 × four × 0.25=8 × four × 0.25=8 × 1 = 8
commutative law of multiplication: letter a × b × c=a × c × B case: 1.25 × seven × 8=1.25 × eight × 7=10 × 7 = 70
the law of multiplicative distribution: denote a with letters ×( b+c)=a × b+a × Case C: 3.35 × 8+3.35 × 2=3.35 ×( 8+2)=3.35 × 10 = 33.5
the nature of division: letter a ÷ b ÷ c=a ÷( b × c) Example: 7.7 ÷ one point two five ÷ 8=7.7 ÷( one point two five × 8)=7.7 ÷ 10 = 0.77
the nature of subtraction: using letters to express a-b-c = a - (B + C) example: 3.78-1.9-1.1 = 3.78 - (1.9 + 1.1) = 3.78-3 = 0.78
the above is the simple operation of decimals that should be mastered by the fifth grade of the new curriculum standard of people's ecation press, in which the law of multiplication and distribution is the key and difficult point
commutative law of multiplication: letter a × b × c=a × c × B case: 1.25 × seven × 8=1.25 × eight × 7=10 × 7 = 70
the law of multiplicative distribution: denote a with letters ×( b+c)=a × b+a × Case C: 3.35 × 8+3.35 × 2=3.35 ×( 8+2)=3.35 × 10 = 33.5
the nature of division: letter a ÷ b ÷ c=a ÷( b × c) Example: 7.7 ÷ one point two five ÷ 8=7.7 ÷( one point two five × 8)=7.7 ÷ 10 = 0.77
the nature of subtraction: using letters to express a-b-c = a - (B + C) example: 3.78-1.9-1.1 = 3.78 - (1.9 + 1.1) = 3.78-3 = 0.78
the above is the simple operation of decimals that should be mastered by the fifth grade of the new curriculum standard of people's ecation press, in which the law of multiplication and distribution is the key and difficult point
5. Unknown_Error
6. End alignment, according to the integer division method. If the divisor and the divisor are both decimal, they are expanded by the same multiple at the same time, and then calculated by integer division.
Hot content