Помогите умоляю...номер 39 ,и 42 умоляю

№ 39
а) 5/6 * (3/10 + 1 1/2) = 1,5
1) 3/10 + 1 1/2 = 3/10 + 3/2 =3/10 + 15/10 = 18/10 = 1,8
Н.О.З : 10

2) 5/6 * 1,8 = 5/6 * 18/10 = 5*18/ 6*10 = 3/2 = 1,5

б) (5/8 +3/4) *1 5/11 = 2
1) 5/8 + 3/4 = 5/8 + 6/8 = 11/8 = 1 3/8
Н.О.З : 8
2) 1 3/8 * 1 5/11 = 11/8 * 16/11 = 11*16/8*11 = 2

в) 1 1/5 * (3/4 - 1/3) =
1) 3/4 - 1/3 = 9/12 - 4/12 =5/12
Н.О.З: 12
2) 1 1/5 * 5/12 = 6/5 * 5*12 = 6*5/5*12 = 1/2 = 0,5