Question

А) 22,5∶5 2/7-2 3/5; б) (7 1/4-6 7/18)∙7,2+2,8

Answer 1

Ответ:

Пошаговое объяснение:

А) 22,5∶5 2/7-2 3/5

22,5:5 2/7=45/2*7/37=315/74

315/74-2 3/5=315/74-13/5=1575/370-

962/370=613/370=1 243/370

б) (7 1/4-6 7/18)∙7,2+2,8=9

7 1/4-6 7/18=7 9/36-6 14/36=31/36

31/36*7,2=31/36*36/5=31/5=6,2

6,2+2,8=9

Answer 2

To solve the expressions А) and б), let's take them step by step:

А) 22.5 : 5 2/7 - 2 3/5

Step 1: Convert mixed fractions to improper fractions: 5 2/7 = (5 * 7 + 2) / 7 = 37 / 7 2 3/5 = (2 * 5 + 3) / 5 = 13 / 5

Step 2: Perform the subtraction within the parentheses first: 37 / 7 - 13 / 5

Step 3: Find a common denominator, which is 35 (7 * 5): (37 * 5) / (7 * 5) - (13 * 7) / (5 * 7) (185 / 35) - (91 / 35)

Step 4: Subtract the fractions: (185 - 91) / 35 = 94 / 35

Step 5: Divide 22.5 by 5 and then subtract the result from the above answer: 22.5 / 5 = 4.5 4.5 - 94 / 35

Step 6: Find a common denominator, which is 35: (4.5 * 35) / 35 - (94 / 35)

Step 7: Perform the subtraction: (157.5 - 94) / 35 = 63.5 / 35

The result is 63.5 / 35.

б) (7 1/4 - 6 7/18) * 7.2 + 2.8

Step 1: Convert mixed fractions to improper fractions: 7 1/4 = (7 * 4 + 1) / 4 = 29 / 4 6 7/18 = (6 * 18 + 7) / 18 = 115 / 18

Step 2: Perform the subtraction within the parentheses first: 29 / 4 - 115 / 18

Step 3: Find a common denominator, which is 36 (4 * 18): (29 * 18) / (4 * 18) - (115 * 4) / (18 * 4) (522 / 36) - (460 / 36)

Step 4: Subtract the fractions: (522 - 460) / 36 = 62 / 36

Step 5: Simplify the fraction (if possible): 62 / 36 = 31 / 18

Step 6: Multiply the above result by 7.2: (31 / 18) * 7.2

Step 7: Multiply the numerators and denominators: (31 * 7.2) / 18

Step 8: Calculate the result: 31 * 7.2 = 223.2 223.2 / 18 = 12.4

Step 9: Add 2.8 to the result: 12.4 + 2.8 = 15.2

The result is 15.2.