a) (1200+60):12

=1200 :12 + 60:12

=100+5

=105

bài này mik lấy trong sách lớp 6 mà pn

(1200+60):12=1260:12=105

(2100+42):21=2142:21=102

(1200+60):12=1200:12+60:12=100+5=105

(2100+42):21=2100:21+42:21=100+2=102

  (1200+60):12

=1200:12+60:12

=100+5

=105

  (2100+42):21

=2100:21+42:21

=100+2

=102

b) 98

a) 105

\(\left(1200+60\right):12=1200:12+60:12\)

\(=100+5=105\)

\(\left(2100-42\right):21=2100:21-42:21\)

\(=100-2=98\)

A) (1200+60):12

=1200:12+60

=100+60

=160

B) (2100-420):21

=2100:21-420

=100-420

=-320

K mk nhé

Giải

a) Ta có: ( 1200 + 60 ): 12

= 1200: 12 + 60:12

= 100+5

= 105

b) Ta có: ( 2100-42):21

= 2100 : 21- 42:21

= 100- 2

= 98

Duyệt đi, chúc bạn học giỏi!

(1200 + 60 ) : 12 = (1200 : 12) + 60 = 100 + 60 =160

(2100 - 42 ) : 21 = (2100 : 21 ) -42 = 100 - 42 = 58   

cho may tra lo truoc

a) (1200 + 60) / 12

= 1200 / 12 + 60 / 12

= 100 + 5

= 105

b) (2100 - 42) / 21

= 2100 / 21 - 42 / 21

= 100 - 2

= 98

a) ( 1200 + 60 ) : 12

   = 1260 : 12

   = 105

b) (2100 - 42) : 21

   = 2058 : 21

   = 98

( 1200 + 60 ) : 12

= 1200 : 12 + 60 : 12

= 100 : 5

= 105

( 2100 - 42 ) : 21

= 2100 : 21 - 42 : 21

= 100 - 2

= 98

( 1200 + 60 ) : 12

= 1200 : 12 + 60 : 12

= 100 + 5

= 105

( 2100 - 42 ) : 21

= 2100 : 21 - 42 : 21

= 100 - 2

= 98

* \(\left(1200+60\right):12=1200:12+60:12=100+5=105\)

* \(\left(2100-42\right):21=2100:21-42:21=100-2=98\)

(k cho tớ với nhá!) 

 ( 1200 + 60 ) : 12                                                 ( 2100 - 42 ) : 21

= 1200 : 12 + 60 : 12                                           = 2100 : 21 - 42 : 21

=    100      +     5                                                =      100    -     2

=            105                                                       =              98

(1200+60):12=105

(2100-42):21=98

a, (1200+60) :12= 1200: 12+ 60:12= 100 +5= 105

b, (2100-42) :21= 2100: 21-42: 21= 100- 2=98

Mình có cách khác nhé :

a ) ( 1200 + 60 ) : 12

= ( 12 x 100 + 12 x 5 ) : 12

= 12 x ( 100 + 5 ) : 12

= 12 x 105 : 12

= 105

b ) ( 2100 - 42 ) : 21

= ( 21 x 100 - 21 x 2 ) : 21

= 21 x ( 100 - 2 ) : 21

= 21 x 98 : 21

= 98

a) (1200+60) : 12=1260 : 12=105

b) (2100-42):21=2058:21=98

\(\left(a\right)\left(1200+60\right)\div12\)

\(=1200\div12+60\div12\)

\(=100+5\)

\(=105\)

\(\left(b\right)\left(2100-42\right)\div21\)

\(=2100\div21-42\div21\)

\(=100+2\)

\(=102\)

\(\text{Đảm bảo đúng! mình học rồi!}\)

a) ( 1200 + 60 ) : 12

= 1200 : 12 + 60 : 12

= 100 + 5

= 105

b) ( 2100 - 42 ) : 21

= 2100 : 21 - 42 : 21

= 100 - 2

= 98