tính nhanh: 6-3.(-1/3)3
Tính nhanh
10+2+4+6+8+20
1/3 + 1/6 + 4/3 + 2/6 + 2/3 + 5/6
(10+20)+(2+8)+(4+6)=30+10+10
=50
1/3+1/6+4/3+2/6+2/3+5/6
=(1/3+4/3+2/3)+(1/6+2/6+5/6)
=7/3+8/6=7/3+4/3=11/3
Tính nhanh 6/5×5/6 - 1/5×7/6×3+3/5 ÷ 6/3
Tính nhanh :
a ) 174 x 78 - 174x68
b ) 1 / 3 + 1/6+ 4/3+2/6+2/3+5/6
a) 174 x 78 - 174 x 68
= 174 x (78-68)
= 174 x 10
= 1740
b) 1/3 +1/6 + 4/3 + 2/6 +2/3 + 5/6
= (1/3 + 2/3 + 4/3) + (1/6 + 2/6 + 5/6)
= 7/3 + 4/3
= 11/3
a) 174 x 78 - 174 x 68
=174 x (78 - 68 )
=174 x 10
=1740
b) 1/3 + 1/6 + 4/3 + 2/6 + 2/3 + 5/6
= (1/3 + 4/3) + (1/6 + 5/6) + (4/3 + 2/3)
= 4/4 + 6/6 + 6/3
= 1 + 1+2
=4
tính nhanh
A=1*2*3+2*4*6+3*6*9/1*3*5+2*6*10+3*9*15
tính nhanh
1+\(\dfrac{1}{2}+\dfrac{3}{4}+\dfrac{3}{6}+\dfrac{6}{8}\)
\(1+\dfrac{1}{2}+\dfrac{3}{4}+\dfrac{3}{6}+\dfrac{6}{8}\)
\(=1+(\dfrac{1}{2}+\dfrac{3}{6})+(\dfrac{3}{4}+\dfrac{6}{8})\)
\(=1+(\dfrac{3}{6}+\dfrac{3}{6})+(\dfrac{6}{8}+\dfrac{6}{8})\)
\(=1+1+1,5=3,5\)
tính nhanh : M = ( 0,5 - 3/5 ) : (-3) + 1/3 - 1/3 -(-1/6) : 2
Bài 1,1+2+3+...+x = 1176
Bài 3 , Tính nhanh :1/1*2+1/2*3 +1/3*4 + ...+ 1/98*99
Bài 4 , Tính nhanh :1/6 +1/12+1/20+ ...+1/110
Bài 5 , Tìm x : 1 /3 +1/6+1/10+...+1/x* (x+1:2)+2009/2011
Bài 3:
= 1- 1/2 + 1/2 -1/3 +...+ 1/98 -1/99
= 1- 1/99
= 98/99
Bài 4:
= 1/2*3 + 1/3*4 + 1/4*5 +...+ 1/10*11
= 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 +...+ 1/10 - 1/11
= 1/2 - 1/11= 9/22
tính nhanh: 1+1+2-3+3+6-9=
tính nhanh:
1+1+2-3+3+6-9
=(1+2-3)+(3+6-9)+1
=0+0+1
=1
Tính nhanh:
a)1/3+2/3+5/12+4/3+1/12 b)3x5/6+5/6+2x5/6
c)___112x113+112x113_________
224x226+224x226