1) (3/4 + 1/5) x 5/19=

2) (12 целых 1/3 - 7 целых 3/4) х 5/19=

3) (2 целых 3/5 - 5/8) : 19 целых 3/4=

4) 9 целых 2/7 х 1 целую 2/5 : 13+6 целых 3/7=

1) (3/4 + 1/5) * 5/19 = (15/20 + 4/20) * 5/19 = 19/20 * 5/19 = 5/20 = 1/4

2) (12.1/3 - 7.3/4) * 5/19 = (12.4/12 - 7.9/12) * 5/19 = (11.16/12 - 7.9/12) * 5/19

= 4.7/12 * 5/19 = 55/12 * 5/19 = 275/228 = 1.47/228

3) (2.3/5 - 5/8) : 19.3/4 = (2,6 - 0,625) : 79/4 = 1,975 : 19,75 = 0,1

4) 9.2/7 * 1 2/5 : 13 + 6.3/7 = 65/7 * 7/5 : 13 + 45/7 = 65/5 : 13 + 45/7 =

= 13 : 13 + 45/7 = 1 + 45/7 = 1 + 6.3/7 = 7.3/7