Сократите 1)17*5/20*34; 2) 36*9/15*30; 3) 7*6*11/33*21*30; 4) 19*9+19*6/19*70-19*25.

Решите задачу:

$1) \frac{17*5}{20*34}= \frac{17*5}{5*4*17*2}= \frac{1}{8} \\ \\ 2)\frac{36*9}{15*30}= \frac{2*3*6*3*3}{5*3*3*2*5}= \frac{6*3}{5*5}= \frac{18}{25}=0,72 \\ \\ 3) \frac{7*6*11}{33*21*30}= \frac{7*3*2*11}{3*11*7*3*30}= \frac{1}{3*15}= \frac{1}{45} \\ \\ 4)\frac{19*9+19*6}{19*70-19*25} = \frac{19(9+6)}{19(70-25)}= \frac{15}{45}= \frac{1}{3}$