\(A=\frac{2}{1.4}+\frac{2}{4.7}+\frac{2}{7.10}+...+\frac{2}{97.100}\)
\(A=2\left(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{97.100}\right)\)
\(A=2\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{97}-\frac{1}{100}\right)\)
\(A=2\left(1-\frac{1}{100}\right)\)
\(A=2.\frac{99}{100}=..............\)
Tự làm nốt nha
1.Tính nhanh:16+(27-7.6)-(94-7-27.99)
2.Tính tổng:A=\(\dfrac{2}{1.4}+\dfrac{2}{4.7}+\dfrac{2}{7.10}+...+\dfrac{2}{97.100}\)
tinh nhanh:16+(27-7.6)-(94.7-27.99)
Câu 1: (4,5 điểm)
a) Tinh nhanh: 23 + (27 - 7.6) - (94.7 - 27.99)
bai1:tinh tong S=1.3+3.5+5.7+...+99.101
bai2 :tinh tong S=1.4+4.7+7.10+...+2017.2020
bai 3: tinh tong N=2.4+4.6+6.8+..+100.102
bai 4: tinh tóng=2.6+6.10+10.14+14.18+...+42.46+50.54
bai 5:tinh tongB=2^2+4^2+6^2+...+100^2
bai 6:C=1^2+3^2+...+100^2
bai7: biet 1^2+2^2+3^2+...+10^2=385 tinh tong 2^2+4^2+6^2+...+20^2
bai 8: tinh tong s=1^2+2^2+3^2+...+99^2
Tính nhanh: 16 + (27-7.6) - (94.7-27.99)
20232-2022.2023
Tính nhanh: 23+(27-7.6)-(94.7-27.99)
2/1.4 + 2/4.7 + 2/7.10 + 2/10.13
giải nhanh giúp mik vs ak
bai 1
cho tong : S = 5 + 8 + 11 +14 = ....
a) tim so hang thu 100 cua tong
b) tinh tong 100 so hang dau tien
bai 2
cho tong : S = 7 + 12 + 17 + 22 + .......
a) tim so hang thu 50 cua tong
b) tinh tong 50 so hang dau tien
bai 3
tinh tong cua tat ca cac so hang tu nhien x , biet x la so tu nhien co 2 chu so va 12 < x <91
ban nao lam ho minh 3 bai tren voi ma ban nao nao lam ra dau tien minh se tich ngay va lun
