Question

вычислите удобным способом : 1) 6 5/8 * 4/9 + 2 3/8 * 4/9 , 2) 17 4/11 * 7/10 - 7/10 * 7 4/11 , 3) 21 9/20 * 10 4/15 + 21 9/20 * 9 11/15 , 4) 12 13/ 19 * 4 3/5 - 7 13/19 * 4 3/5

Answer 1

1) 4/9(6 5/8+ 2 3/8)=4/9*8 8/8= 4/9*9=4
2) 7/10(17 4/11 - 7 4/11)= 7/10*10=7
3) 21 9/20(10 4/15+ 9 11/15) = (21*20+9)/20 * 20=420+9=429
4) 4 3/5 ( 12 13/19-7 13/19)= (4*5+3)/5 * 5= 23