\(4S=15+17+19+21+...+151+153+155\)
\(\Leftrightarrow4S=\frac{\left(15+155\right)\left[\left(155-15\right)\div2+1\right]}{2}\)
\(\Leftrightarrow4S=\frac{170.\left[140\div2+1\right]}{2}\)
\(\Leftrightarrow4S=\frac{170.\left[70+1\right]}{2}\)
\(\Leftrightarrow4S=\frac{170.71}{2}\)
\(\Leftrightarrow4S=85.71\)
\(\Leftrightarrow4S=6035\)
\(\Leftrightarrow S=\frac{6035}{4}\)
S1= 1+2+3+...+999
S2=21+23+25+...+1001
S3=23+24+...+127+128
S4=15+17+19+21+...+151+153+155
Tính tổng.
S1=10+12+14+....+2010
S2=21+23+25+...+1001
S3=1+4+7+....+79
S4=15+17+19+21+....+151+153+155
s5=15+17+19+21+...+151+153+155
F=15=17=19=21=.......=151=153=155
cho em hoi cau nay lam sao ak
A) S1=1+2+3+...+999
B) S2=21+23+25+...1001
C)S3=+23+24+...+127+128
D)S4=15+17+19+21+...+151+153+155
tính Tổng : S= 15+17-19-21+23+25-27-29+...+151+153-155
Bài 5*. Tính tổng:
S1 = 1 + 2 + 3 + …+ 999
S2 = 21 + 23 + 25 + … + 1001
S3 = 23 + 24 + … + 127 + 128
S4 = 15 + 17 + 19 + 21 + … + 151 + 153 + 155
tinh tong
S=1+2+3+...+999
S=15+17+19+21+...+151+153+155
Tính tổng
S1 = 1 + 2 + 3 +....+ 999
S2 = 10 + 12 + 14 +....+ 2010
S3 = 21 + 23 + 25 +....+ 1001
S4 = 24 + 25 + 26 +....+ 125 + 126
S5 = 1 + 4 + 7 +.......+ 79
S6 = 15 + 17 + 19 + 21 +....+ 151 + 153 + 155
S7 = 15 + 25 + 35 +....+ 115
Giải cụ thể ra nha!!!!Mình đang cần gấp!!!!
