Question

3 1/7 * (-4)- 1,8 : 0,1)+ 20/21

Answer 1

Вроде так, там в скобках минус или умножить?

Answer 2

To solve the expression 3 + 1/7 * (-4) - 1.8 / 0.1 + 20/21, we can follow the order of operations, which is commonly known as PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).

Let's break it down step by step:

Step 1: Parentheses In this expression, there are no parentheses, so we move to the next step.

Step 2: Exponents Again, there are no exponents in the expression, so we move on.

Step 3: Multiplication and Division We start from left to right. The expression 1/7 * (-4) can be simplified as follows: 1/7 * (-4) = -4/7

Next, we have 1.8 / 0.1, which can be simplified as: 1.8 / 0.1 = 18

Now, we substitute these simplified values back into the original expression:

3 + (-4/7) - 18 + 20/21

Step 4: Addition and Subtraction Again, we start from left to right. Let's simplify the expression further:

3 + (-4/7) - 18 + 20/21 = 21/7 + (-4/7) - 18 + 20/21 = (21 - 4)/7 - 18 + 20/21 = 17/7 - 18 + 20/21

To add or subtract fractions, we need a common denominator. In this case, the common denominator is 7 * 21 = 147.

Converting the fractions to have a common denominator:

(17 * 21)/(7 * 21) - (18 * 21)/(21) + (20 * 7)/(21 * 7) = 357/147 - 378/21 + 140/147

Now, let's simplify:

357/147 - 378/21 + 140/147 = (357 * 3)/(147 * 3) - (378 * 7)/(21 * 7) + 140/147 = 1071/441 - 2646/147 + 140/147 = (1071 - 2646 + 140)/441 = (-1435 + 140)/441 = -1295/441

The final simplified result is -1295/441.

Therefore, the answer to the expression 3 + 1/7 * (-4) - 1.8 / 0.1 + 20/21 is -1295/441.