1)7цел.5 шестых-6цел.три восьмых+3цел.семь девятых=? решить по деяньям -(4цел.три четвёртых - 3,75)+(9цел.5

1

7 5/6 - 6 3/8 + 3 7/9 = 377/72 = 5 17/72.

1) 7 5/6 - 6 3/8 = 47/6 - 51/8 = (47 * 4)/(6 * 4) - (51 * 3)/(8 * 3) = 188/24 - 153/24 = 35/24 = 1 11/24;

2) 1 11/24 + 3 7/9 = 35/24 + 34/9 = (35 * 3)/(24 * 3) + (34 * 8)/(9 * 8) = 105/72 + 272/72 = 377/72 = 5 17/72.

2

 -(4 3/4 - 3,75) + (9 5/6 - 3 17/18) = 1 22/45.

1) 4 3/4 - 3,75 = 19/4 - 35/100 = (19 * 25)/(4 * 25) - 35/100 = 475/100 - 35/100 = 440/100 = 44/10 = 4 4/10 = 4 2/5;

2) 9 5/6 - 3 17/18 = 59/6 - 71/18 = (59 * 3)/(6 * 3) - 71/18 = 177/18 - 71/18 = 106/18 = 5 16/18 = 5 8/9;

3) -4 2/5 + 5 8/9 = -44/10 + 53/9 = (-44 * 9)/(10 * 9) + (53 * 10)/(9 * 10) = -396/90 + 530/90 = 134/90 = 1 44/90 = 1 22/45.