S = 1 + (-2) + 3 + (-4) + ... + (-98) + 99
= [1 + 99] + [( - 2) + (- 98)] + ... + [49 + 51] + (-50)
= 100 + (-100) + ... + 100 - 50
= 100 - 50
= 50
S = 1 + (-2) + 3 + (-4) + ... + (-98) + 99
= -1 + (-1) + ... + (-1) + 99
= (-49) + 99
= 50
tinh tong sau = 2 cach s= 1+ (-2) +3 +(-4) + ......+(-98) + 99
tinh nhanh bang hai cach : S = 1+(-2)+3+(-4)+...+(-98)+99
S=?
A= 1-2+3-4+…+-98+99
Tinh tong sau mot cach hop ly
bai1.Tinh tong cua cac so nguyen am tu -1738 den -16
bai2.Tinh tong sau bang 2 cach
A=1+(-2)+3+(-4)+....+99+(-100)
Tinh tong sau bang cach hop li nhat: (1+3+5+...+99)-(2+4+6+...+100)
tinh tong sau bang 2 cach
a. \(A=1+\left(-2\right)+3+\left(-4\right)+...+\left(-98\right)+99\)
b.\(B=1+\left(-4\right)+7+\left(-10\right)+...+319+\left(-322\right)+325\)
tinh tong s=1*100+2*99+3*98+..+49*51+50*50
Tinh tong
1+2-3-4+...+97+98-99-100
tinh tong sau bang cach hop ly
a = 2+2^2+2^3+2^4+...+2^100
mong moi nguoi giup do