a) tự làm
b) (57-17)+(58-18)+(59-19)+(60-20)+(61-21)=40+40+40+40+40=200
c) (9+15)+(11+13)+(-10-14)+(-12-12-4)=24+24-24-24-4=-4
d)-(1+2+3+.....+2007)=\(-\dfrac{\left(1+2007\right).2007}{2}=-2015028\)
Câu 2: Tính
a/ 30 - 4. (12 + 15)
b/ -16 . 21 + 16 . 63 + 58 . 16
c/ (+12).21 + 21.(-22)
d/ 126 – ( - 4) + 7 – 20
e/ 210 + [46 + (–210) + (–26)]
g/ 100 + (-430) + 2145 + 530
h/ 8. 12 - 8. 5
i/ 25.134 + 25.(-34)
f/ 23 - |19 – 81|.2
Tính :
a) \(5+\left(-7\right)+9+\left(-11\right)+13+\left(-15\right)\)
b) \(\left(-6\right)+8+\left(-10\right)+12+\left(-14\right)+16\)
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]}
1) Tính tổng:
a) 1+(-2)+3+(-4)+5+(-6)+14+(-20)+21+(-22)
b)Tính tổng tất cả các số nguyên x biết:
-10<x\(\le\)10
(7/12+5/-18):(-61/9)
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)
Bài 1:
a, 3 + ( -12 ) + | 3 | + ( -22 ) + 23 + ( -32 ) + ... + 93 + ( -102 )
b, 5 + ( -15 ) + ( -25 ) + 35 + 45 + ( -55 ) + ( -65 ) + ... + 1995 + 2005
Nhanh lên nhé ! Chiều mai mình nộp rồi.
Tính :
a) \(1+\left(-3\right)+5+\left(-7\right)+9+\left(-11\right)\)
b) \(\left(-2\right)+4+\left(-6\right)+8+\left(-10\right)+12\)