Tính nhanh:
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+10+5
= 10 + 10 + 10 + 10 + 10+5
= 50 + 5
= 55
123*45+123*50+123*5
= 123*(45+50+5)
= 123 * 100
= 12300
K mk nha bn
1+2+3+4+5+6+7+8+9+10
= ( 1+10 ) + ( 2+9) + (3+8) + (4+7) + (5+6)
= 11 + 11 + 11 + 11 + 11
=11 x 5
=55
123 x 45 + 123 x 50 + 123 x 5
= 123 x ( 45 + 50 +5 )
= 123 x 100
=12300
hok tốt .
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 10 : 2 x 11 = 55
123 x 45 + 123 x 50 + 123 x 5 = 123x ( 45 + 50 + 5) = 123 x 100 = 12300
Tính nhanh :
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= ( 1 + 10 ) + ( 2 + 9 ) + ( 3 + 8 ) + ( 4 + 7 ) + ( 5 + 6 )
= 11 + 11 + 11 + 11 + 11
= 11 x 5 = 55
123 x 45 + 123 x 50 + 123 x 5
= 123 x ( 45 + 50 + 5 )
= 123 x 100 = 12 300
Tính nhanh:
Bài 1:
1+2+3+4+5+6+7+8+9+10 = (1+9) + (2+8) + (3 + 7) + (4 + 6) + 10 + 5
= 10 + 10 + 10 + 10 + 10 + 5
= 55
Bài 2:
123 x 45 + 123 x 50 + 123 x 5 = 123 x (45 + 50 + 5)
= 123 x 100
= 12300
Goodluck!!
a} = ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 10 + 5
= 10 + 10 + 10 + 10 +10 + 5
= 55
b.
= 123 * ( 45 + 50 + 5 )
= 123 * 100
= 12300
Mình điền dấu nhân là * nhé
Tính nhanh :
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 10 + 5
= 10 + 10 + 10 + 10 + 10 + 5
= 50 + 5
= 55
123 x 45 + 123 x 50 + 123 x 5
= 123 x ( 45 + 50 + 5 )
= 123 x 100
= 12300
~ Hok Tốt ~
(1+9) + (2+8) +(4+6) +5+10=10+10+10+10+5=40+5=45
123*(45+50+5)=123* 100=12300
1+2+3+4+5+6+..+9+10
=(10+1)+(9+2)+(8+3)+...+(6+5)
=11x5
=55
123x45+123x50+123x5
=123(45+5+50)
=123x100
=12300
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+10+5
=10+10+10+10+10+5
=10×5+5
=50+5
=55
123×45+123×50+123×5
=123×(45+50+5)
=123×100
=12 300
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+10+5
= 10 + 10 + 10 + 10 + 10+5
= 50 + 5
= 55
123*45+123*50+123*5
= 123*(45+50+5)
= 123 * 100
= 12300
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+(5+10)
= 10+10+10+10+15
=40+15
=55
123x45+123x50+123x5
=123x(45+50+5)
=123x100
=12300
Chúc bạn học tốt^^
