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

1¹=1

123 x 10 = 1230

11²=121

123 + 0 = 123

1¹=1

123x10=1230

11²=121

123+0=123

\(1^1=1\)

\(123.10=1230\)

\(11^2=121\)

\(123+0=123\)

\(nha^{ }\)

12 : 3 = 4 x 4 = 16

20 x 3 = 60

90 : 1 = 90

123 - 123 = 0

10 x 9 = 90 : 9 = 10

12 - 9 = 3 x 9 = 27

23 - 5 = 18

123 + 12 = 135

1000 - 200 = 800

333 - 111 = 222

\(20.3=60\)

\(90.1=90\)

\(123-123=0\)

\(10.9=\frac{810}{9}=90\)

\(23-5=15\)

\(123+12=135\)

\(1000-200=800\)

\(333-111=222\)

1000 + 100 + 10 + 1 

= 1111

1000 = 10 x 10 x 10 ( 10 x 100 )

123 x 10 = 1230

=1111

=900+100

=1230 knha

1000+100+10+1

=  1100+11

=  1111

 1000

= 10x10

123x10

= 1230

123 + 10 + 10 x 10 - 10

= 133 + 10 + 100 - 10

= 143 + 100 - 10

= 243 - 10

= 233

123 + 10 + 10 x 10 - 10

= 123 + 10 + 100 - 10

= 123 + 100 + (10 - 10)

= 123 + 100 + 0

=    223

đáp án là 15460 đó bạn

123 x 10 + 513 x 10 + 364 x 5 x 2 

= 123 x 10 + 513 x 10 + 364 x 10

= 10 x ( 123 + 513 + 364 )

= 10 x 1000

= 10 000

15460 nha bạn