TÍnh nhanh
a,(2+4+6+…+100) * (36*333-108*111)
b,S=1+2+3+4+5+…+99+100+101+102
c,S=101+103+105+…+197+199+201
d,S=2+5+8+11+…+293+296
đ,S=7+11+15+19+…+279+283
e,S=1+2+3+…+2002+2003+2005
g, 5+10+15+…+205+210+215
h,367+361+355+…+7+1
Em đang cần gấp ạ
TÍnh nhanh a,(2+4+6+…+100) * (36*333-108*111) b,S=1+2+3+4+5+…+99+100+101+102 c,S=101+103+105+…+197+199+201 d,S=2+5+8+11+…+293+296 đ,S=7+11+1
By Liliana
Đáp án:
a. 0 ; b. 5253 ; c. 7701 ; d. 14751 ; đ. 10150 ; e. 2009011 ; g. 4730 ; h. 11408
Giải thích các bước giải:
a. (2+4+6+…+100) x (36 x 333-108 x 111)
= (2+4+6+…+100) x (36 x 3 x 111-108 x 111)
= (2+4+6+…+100) x (108 x 111-108 x 111)
= (2+4+6+…+100) x 0
= 0
b. S = 1+2+3+4+5+…+99+100+101+102
SSH = (102-1) : 1 + 1
SSH = 102
S = (102+1) x 102 : 2
S = 5253
c. S = 101+103+105+…+197+199+201
SSH = (201-101) : 2 + 1
SSH = 51
S = (201+101) x 51 : 2
S = 7701
d. S = 2+5+8+11+…+293+296
SSH =(296-2) : 3 + 1
SSH = 99
S = (296+2) x 99 : 2
S = 14751
đ. S = 7+11+15+19+…+279+283
SSH = (283-7) : 4 + 1
SSH = 70
S = (283+7) x 70 : 2
S = 10150
e. S = 1+2+3+…+2002+2003+2005
Đặt A = 1 + 2 + 3 + … + 2003
SSH dãy A = (2003 – 1) : 1 + 1 = 2003
A = (2003 + 1) x 2003 : 2
A = 2007006
⇒ 1 + 2 + 3 + 4 + … + 2003 + 2005 = 2009011
g. 5+10+15+…+205+210+215
SSH = (215-5) : 5 + 1
SSH = 43
= (215+5) x 43 : 2
= 4730
h. 367+361+355+…+7+1
SSH = (367-1) : 6 + 1
SSH = 62
= (367+1) x 62 : 2
= 11408