1:)1: 1+(-2)+3+(-4)+........+19+(-20)
=1-2+3-4+.....+19-20
=-1+(-1)+..........+(-1)
=-1.(20-1)+1:2
=-1.10
=-10
2: 1- 2 +3 -4+......+99 - 100
=( 1- 2) +(3 -4)+......+(99 - 100)
=-1+(-1)+.....+(-1)
=-1.(100-1)+1:2
=-1.50
=-50
3: 2 - 4+6 - 8+.....+48 - 50
=(2 - 4)+(6 - 8)+.....+(48 - 50)
=-2+(-2)+......+(-2)
=-2.(50-2):2+1
=-2.25
=-50
4: -1 + 3 - 5 +7 -.....+97 - 99
=-1 +(3-5)+(7-9)+.......+(97-99)
=-1+(-2)+(-2)+........+(-2)
=-1+[(-2).(99-3):2+1]
=-1+[(-2).49]
=-1+(-98)
=-99
1 + (-2) + 3 + (-4) + 5 +(-6) + ... + 99 + (-100)
giúp mình giải nha , mình thả tim cho .
lập luận và giải luôn nhé.
<3 , <3 ,<3
6) x-1/2=9/2
7) x+5/4=-3/4
8) x+2/7=5/7
9) x-4/3=1/3
10) x+5/2=-7/2
1) x+1/3=-7/3 4) 2/3+x=7/3
2) 1/8-x=3/8 5) x--7/3=5/3
3) x-4/5=6/5
1) x+1/2=-5/3
2) 1/3-x=3/5
4) x-4/3=-7/9
5) x--7/3=5/6
6) x-1/5=9/10
7) x+5/12=3/8
8) 5/4=7/6
9) x-2/7=1/35
10) x-2/7=-7/10
cả phép tính nữa nha
1) x+1/2=-5/3
2) 1/3-x=3/5
4) x-4/3=-7/9
5) x--7/3=5/6
6) x-1/5=9/10
7) x+5/12=3/8
8) x+5/4=7/6
9) x-2/7=1/35
10) x-2/7=-7/10
1.Tính tổng:
S=x+|x|+x+|x|+x+|x|+x+|x|+x+|x|+x
2.Tính tổng
S1=1+(-2)+3+(-4)+...+(-2018)
S2=1+(-3)+5+(-7)+...+(+2001)
S3=1+(-2)+(-3)+4+5+(-6)+(-7)+8+9
Bài 4
1) 8 2/7-(4 2/7-3 4/9)
2) (10 2/9+2 3/5)-6 2/9
3) 11 3/13-(2 4/7+5 3/13)
a/ 53 : 52 + 96 c/ 17.75 + 17.25 – 125 e/ 21.16 + 37.21 + 21.63
b/ 25.7.5.4.2 d/ 25.124 – 24.25 + 212 f/ 35.48 + 65.68 + 20.35
h/ 711: 79 - 62 + 23.2 g/ 117:{[79 – 3(33 – 17 )]:7 + 2} m/ 27:23 + 23.20 - 110
n/ 52 + [250 – 150 :(35.22 – 90)] p/ 3978 : [359 – (27:24 + 39.8]
q/ 12 + 15 + 18 +…+ 90 k/ 8 + 12 + 16 +…+ 100 l/ 7 + 11 +15 +…+ 43 + 47
r/ 1 + 6 +11 + …+ 46 +51 t/ 20 – [30 – (5 – 1)2] v/80 –[130 – (12 -4)2]
s/ 80 – 4.52 + 3.23 o/ 140:{80 – [130 – (12 -4)2]}
tính
( 6- 2\(\dfrac{4}{5}\)). 3\(\dfrac{1}{8}\)- 1\(\dfrac{3}{5}\): \(\dfrac{1}{4}\)
