tinh bang cach thuan tien nhat : 1+2-3-4+5+6-7-8+9+...+2013+2014-2015-2016
1+2+3+4+5+6+7+8+9
tinh bang cach thuan tien nhat
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) +5
= 10 + 10 + 10 +10 + 5
= 10 x 4 + 5
= 40 + 5
= 45
1+2+3+4+5+6+7+8+9
=[1+9]+[2+8]+[3+7]+[4+6]+5
=10+10+10+10+5
=40+5
=45
tinh bang cach thuan tien nhat
1+2+3+4+5+6+7+8+9:9 =
1+2+3+4+5+6+7+8+9:9
=1+2+3+4+5+6+7+8+1
=(1+1)+(2+8)+(3+7)+(4+6)+5
=2+10+10+10+5
=(2+5)+(10+10+10)
=7+30
=37
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 : 9
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5 : 9
= 10 + 10 + 10 + 10 + 5 : 9
= 20 + 20 + 5 : 9
= 40 + 5 : 9
= 45 : 9
= 5
tinh bang cach thuan tien nhat : 3/4 x 4/5 + 5/6 x 6/7 x 7/8
Tinh bang cach thuan tien nhat
3/2 + 4/9 + 4/7 + 5/9
tinh bang cach thuan tien nhat a.3/5+4/7+2/5+1/7+2/7 b.1/3+1/6+4/3+2/6+2/3
Tinh gia tri bieu thuc bang cach thuan tien nhat :
A= 1/10 x 2/9 x 3/8 x 4/7 x 5/6 x 6/5 x 7/4 x 8/3 x 9/2
Tinh bang cach thuan tien nhat
2 phan 9+1 phan 5 +7 phan 9 +4 phan 5
\(\frac{2}{9}+\frac{1}{5}+\frac{7}{9}+\frac{4}{5}=\left(\frac{2}{9}+\frac{7}{9}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)=\frac{9}{9}+\frac{5}{5}=1+1=2\)
\(\frac{2}{9}+\frac{1}{5}+\frac{7}{9}+\frac{4}{5}=\left(\frac{2}{9}+\frac{7}{9}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)=1+1=2\)
tinh bang cach thuan tien nhat
a(6/11 + 5/11)*3/7
b.3/5 * 7/9 +3/5*2/9
c.(6/7 - 4/7) : 2/5
d.(8/15 : 2/11 + 7/15 : 2/11
bai 4: tinh bang cach thuan tien nhat: a, 5/9*5/2+4/9*5/2 , b, 12*3/4-3/4*12/7 lam kieu gi
giup minh voi
\(a,\dfrac{5}{9}\times\dfrac{5}{2}+\dfrac{4}{9}\times\dfrac{5}{2}=\dfrac{5}{2}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)=\dfrac{5}{2}\times1=\dfrac{5}{2}\)
\(12\times\dfrac{3}{4}-\dfrac{3}{4}\times\dfrac{12}{7}=\dfrac{3}{4}\times\left(12-\dfrac{12}{7}\right)=\dfrac{3}{4}\times\dfrac{72}{7}=\dfrac{54}{7}\)