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How to calculate the percentage in mathematics

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A calculator with the appropriate option is not always at hand

With the need to calculate the percentage of peopleCollides constantly, sometimes even without realizing it. And not only in the math exam, but also, for example, trying to determine what part of the total income of the family is utility bills or payment for a kindergarten.

And many people need to count percentages at a dead end.

Instructions

    1

Understand that the number from which you need toCalculate interest - it's always one hundred percent. Regardless of whether it is set in the task or you found it yourself, having combined the incomes of all members of the family. It can be designated, for example, by the letter a or any other letter, or it can be generally not designated.

    2

Find from this number 1 percent. To do this, divide the original number by 100. If we take the general formula, then 1 percent of the number a will be equal to a / 100.

    3

Let's say you need to find not 1 percent, but 20 percent. Then the number, which denotes 1 percent of the given, must be multiplied by the necessary number of percentages. That is, you get a / 100 * 20. For example, your salary is 11 000 rubles. 1% of this number is 110 rubles, and 20% -2,200 rubles.

    4

Let's say the task requires you to find out how muchPercent of the original number a is b. The number of percent to be found is x. Find 1%, which will be a / 100. In order to determine how many percent of the number a is the number b, you need to divide it by the amount obtained. Remember the rules for dividing an integer by a fraction. It is necessary to divide the number by the numerator of the fraction (in this case by a) and multiply by its denominator (in this case 100): x = b / a * 100. For example, 250 bags of potatoes were brought to the warehouse. 35 the storekeeper immediately sent to the store, and he needs to know how much this is a percentage of the total number of bags. Find 1%, which in this task will be 250/100 = 2.5 bags. Dividing 35 by 2.5, you get the desired value - 14%.

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