1. 1 7/8 + ( 1 3/5 + 1 1/8) = 5 1/10
1) 1 3/5 +1 1/8 = 1 24/40 + 1 5/40 = 2 29/40
2) 1 7/8 +2 29/40 = 1 35/40 + 2 29/40 = 3 + 84/40 =
=3+ 2 4/40 = 5 4/40 =5 1/10
2. 7 1/2 - (1 3/8+1 1/2) =4 5/8
1) 1 3/8+ 1 1/2 =1 3/8 +1 4/8 = 2 7/8
2) 7 1/2 - 2 7/8 = 7 4/8 -2 7/8 =
= 60/8 - 23/8= 37/8= 4 5/8
3. 9 1/16 - (5/8+7/16)=8
1) 5/8+7/16= 10/16 +7/16 = 17/16= 1 1/16
2) 9 1/16 - 1 1/16 = 8
4. 7 3/4 + (2 7/8 - 1 3/4)= 8 7/8
1) 2 7/8 - 1 3/4 = 2 7/8 -1 6/8 = 1 1/8
2) 7 3/4 +1 1/8 = 7 6/8 + 1 1/8= 8 7/8
1)=(25/6÷10/3×2/10+5/6)×3+0.75=
=(25/6×3/10×1/5+5/6)×3+0.75=
=(1/4+5/6)×3+0.75=(3/12+10/12)×3+0.75=
=13/12×3+75/100=13/4+3/4=16/4=4
2)=(0.4+2.6-1 5/8)÷75/100=
=(3-1 5/8)÷3/4=1 3/8÷3/4=11/8×4/3=11/6=
=1 5/6
6 кг правильный ответ, т.к. сказано что
масса арбуза + масса арбуза/2=9
отсюда следует, что 6+ 6/2=9