bai 1 : a = 1.2+2.3+3.4+4.5+5.6+............+99.100
1.3+3.5+5.7 +9.11 +..........+2011.2013
1+4+9+16+ ...............+ 9801+10000
a=1.2.3+2.3.4+..........+98.99.100
bai 2 : a ) [ -2008.57+1004.(-86 )]:[32.74+16.(-48)
b) 1+2-3-4+5+6-7-8+9+10-.........................+2006-2007-2008+2009
Tính: A=1.3+3.5+5.7+....+101.103
câu 2) A=1.2+3.4+5.6+....+99.100
xog nhanh tích luôn
Bài 1: Tính tổng:
A= 1.2+3.4+5.6+...+21.22
B = 1.3+5.7+9.11+...+41.43
C = 12.2+ 22.3 + 32.4 + ...+ 212.22
Bài 2: Tính
A = 13 + 23 + ...+ 1003
B=23 + 43 + 63 + ...+ 1003
A=1.2+2.3+3.4+..........+99.100
B=1.3+3.5+5.7+...........+97.99
C=1.2.3+2.3.4+............98.99.100
A=1.2+2.3+3.4+...........+99.100
B=1.3+3.5+5.7+............+97.99
C=1.2.3+2.3.4+.............+98.99.100
tính hợp lí:
a 2.53.12+4.6.87-3.8.40
b C=4/5.7+4/7.9+...+4/59.61
c B=1.2+2.3+3.4+...+99.100
d E=1.2+3.4+5.6+...+99.100
F=1.4+2.5+3.6+....+97.100
a)B= 2.4 + 4.6 +6.8 +.....+18.20
b)C= 1.3+3.5+5.7+......+19.21
c) G= 1.2+2.3+3.4+......+99.100
Tính nhanh
Bài 1:Tính:
a,3 14/19 + 13/17 + 35/43 + 6 5/19 + 8/13
b,130 25/28 + 120 17/35
c,17 2/31 - (15/17 + 6 2/31)
d,(31 6/13 + 5 9/41) - 31 6/13
e,(17 24/31 - 3 7/8) - (2 38/31 - 4)
g,1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 + 1/5.6
h,1/1.2 + 1/2.3 + 1/3.4 + .........+ 1/49.100
i,1/1.3 + 1/3.5 + 1/5.7 +........+ 1/97.99
giải giùm nhé
Tính:A=1.2+2.3+3.4+4.5+5.6+...+199.200