Question

,1, tính

a,1+ 6+11+........+111+116

b, 827.715-827.600-827.114

c, 93.27+93.15+93.3+7.45

d, 27.18+52.39--27.8-52.29

2, tìm x , biết

a, 2 : (x+3)-5 = 5

b, 70:(10-x) +3 = 13

c, 71-3.x:8=41

d, 32-x:8=28

LƯU Ý : ĐẤU . LÀ NHÂN

Answer 1

b, 827 . 715 -827 .600 - 827.114

 =827.(715-600-114)

=827.1

=827

c, 93.27+93.15+93.3+7.45

=93.(27+15+3) +7.45

=93.45 +7.45

=(93+7).45

=100.45

=4500

d, 27.18+52.39-27.8-52.29

=27.18-27.8+52.39-52.29

=27.(18-8)+52.(9-29)

=27.10+52.10

=270+520

=790

B2

a, 2:(x+3)-5=5

2:(x+3)=5+5

2:(x+3)=10

x+3=2:10

x+3=1/5

x=1/5-3

x=-14/5

b, 70 : (10-x)+3=13

70:(10-x)=13-3

70:(10-x)=10

10-x= 70:10

10-x= 7

x=10-7

x=3

c, 71-3.8:x=41

3.8:x= 71-41

3.8:x= 30

24:x=30

x=24:30

x=4/5

d, 32-x:8 =28

   x:8= 32-28

x:8=4

x=-4.8

x=-32