biet n!=1.2.3....n.tinh 1. 1 ! +2 . 2 ! +3 . 3 ! +4 . 4 !+ 5 . 5 ! =.................................
Cau 1: Tim n biet : 5/8 + 5/24 + 5/48 + 5/80 + ... + 5/2n + 2 . 2n + 4 = 189/112
Cau 2 : Cho A = 1 + 1/1.2 + 1/1.2.3 + ... + 1/1.2.3...2014. So sanh A voi 2
Cau 3 : Tim n biet : 5/3 + 5/15 + 5/35 + 5/63 +...+ 5/2n + 1 . 2n + 3 = 172/69
Thực hiện phép tính ( tính nhanh nếu có thể )
1, 11 3/13-(2 4/7+5 3/13)
2, 19 5/8:7/12+(-15 1/4):7/12
3, 2/5.1/3-2 2/15:1/5+3/5.1/3
4, (3 1/3+2,5):(3 1/6-4 1/5)-11/31
5, 75%-1 1/5+0,5:5/12-(-1/2)2
Tính giá trị biểu thức
a) 2/5.1/3-2/15:1/5+3/5.1/3
b) 4/2.4+4/4.6+4/6.8+....+4/2008.2010
3x.(1/1.1/2+1/2.1/3+1/3.1/4+1/4.1/5+1/5.1/6)=3/4
biet n! =1*2**3*...*n . tinh 1*1!+2*2!+3*3!+4*4!+5*5!=?
1.Tinh nhanh :
A)1/5.1/4+2/3-1/2=?
B)12.4.6,5+1/2=?
C)(8+4).(5-5)=?
( tính nhanh )
a,8/40+-14/35-12/60 b,5/7.5/11+5/7.5/11-5/7.14/11 c,19 5/8: 7/12-15 1/4:7/12
d, 2/5.1/3-2/15:1/5+ 3/5.1/3 e,4/9.19 1/3 - 4/9.39 1/3 g,81.17-15.81/81.17-81.15
Thực hiện phép tính (Tính hợp lý nếu có thể)
a) 2/5.1/3-2/15:1/5+3/5.1/3
b) \(\left(6-2\frac{4}{5}\right).3\frac{1}{8}+1\frac{3}{8}:\frac{1}{4}\)
Mong mn giúp ạ! Ai nhanh mik tick!