( 3 целых+ 0,45) × 1 целая 2/3 + ( 4,2 - 2/35) : 4 целых 1/7= 4 3/4.
1)) 3+ 0,45= 3,45= 345/100= 69/20;
2)) 69/20• 1 2/3= 69/20• (1•3+2)/3=
69/20• 5/3= 23/4• 1/1= 23/4= 5 3/4;
3)) 4,2- 2/35= 42/10- 2/35= 21/5- 2/35=
(21•7)/(5•7)- 2/35= 147/35- 2/35=
145/35= 4 5/35= 4 1/7.
4)) 4 1/7: 4 1/7= (4•7+1)/7: (4•7+1)/7=
29/7: 29/7= 29/7• 7/29= 1/1•1/1=1;
5)) 5 3/4- 1= 4 3/4.