Question

1) 1/7 - 2/21 + 1/8 + 3/4 = ? 2) 3/5 + 1/5 + 7/15 - 3/15 = ? 3) 7/12 - 5/12 + 5/6 - 4/6 = ? ПЖ СРОЧННООО

Answer 1

Ответ:

Пошаговое объяснение:

1) 1/7 - 2/21 + 1/8 + 3/4 =

3/21 - 2/21 + 1/8 + 6/8 =

1/21 + 7/8 = 8/168 + 147/168 = 155/168

2) 3/5 + 1/5 + 7/15 - 3/15 =

4/5 + 7/15 - 3/15 =

12/15 + 7/15 - 3/15 = 16/15 =

1. 1/15

3) 7/12 - 5/12 + 5/6 - 4/6 =

2/12 + 1/6 = 1/6 + 1/6 = 2/6 = 1/3

Answer 2

Let's solve these math problems:

1. 1/7 - 2/21 + 1/8 + 3/4: To add or subtract fractions, you need a common denominator. In this case, the common denominator is 168, which is the least common multiple of 7, 21, 8, and 4.

(24/168) - (16/168) + (21/168) + (126/168)

Now, you can add and subtract the fractions:

(24 - 16 + 21 + 126) / 168

(55 + 126) / 168

181/168

To simplify the fraction, you can divide both the numerator and denominator by their greatest common divisor, which is 1:

(181/1) / (168/1) = 181/168

So, 1/7 - 2/21 + 1/8 + 3/4 = 181/168.

2. 3/5 + 1/5 + 7/15 - 3/15: These fractions already have a common denominator of 15, so you can directly add and subtract them:

(3/15) + (1/15) + (7/15) - (3/15)

Now, add and subtract the fractions:

(3 + 1 + 7 - 3) / 15

(8/15)

So, 3/5 + 1/5 + 7/15 - 3/15 = 8/15.

3. 7/12 - 5/12 + 5/6 - 4/6: These fractions also have a common denominator of 12, so you can directly add and subtract them:

(7/12) - (5/12) + (10/12) - (8/12)

Now, add and subtract the fractions:

(7 - 5 + 10 - 8) / 12

(4/12)

To simplify the fraction, you can divide both the numerator and denominator by their greatest common divisor, which is 4:

(4/4) / (12/4) = 1/3

So, 7/12 - 5/12 + 5/6 - 4/6 = 1/3.

Пожалуйста, вот ваши ответы:

1. 1/7 - 2/21 + 1/8 + 3/4 = 181/168.
2. 3/5 + 1/5 + 7/15 - 3/15 = 8/15.
3. 7/12 - 5/12 + 5/6 - 4/6 = 1/3.