a: Số số hạng là:

(24-2):2+1=12(số)

Tổng là:

\(\dfrac{26\cdot12}{2}=26\cdot6=156\)

tớ đồng ý với kết quả của Nuyễn Lê Phước Thịnh

Hướng dẫn giải:

a) (9 + 48) : 3 = 9 : 3 + 48 : 3 = 3 + 16 = 19

b) (36 + 24) : 3 = 60 : 3 = 20

c) 160 : 5 + 40 : 5 = (160 + 40) : 5 = 200 : 5 = 40

d) 90 : 5 + 110 : 5 = (90 + 110) : 5 = 200 : 5 = 40 

0,6 

3/5x6/7+3/5x16/14-3/5x1

=3/5x(6/7+16/14-1)

=3/5x1

=3/5

A) 9135 : 9 + 765 : 9

= ( 9135+765 ) : 9 

= 9900 : 9

= 1100

Hok Tốt.

a)

= (9135+765):9

=9900:9

= 1100

k mk nhé

B) 9648 : 8 - 1640 : 8

=  ( 9648 - 1640 ) : 8

= 8008 : 8

= 1001

Học Tốt !

1/2+1/4+1/8+1/16+1/32+1/64

=(1/2+1/4+1/8)+(1/16+1/32+1/64)

=(4/8+2/8+1/8)+(4/64+2/64+1/64)

=7/8+7/64

=56/64+7/64

=63/64

           B =        \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) +  \(\dfrac{1}{16}\)  + \(\dfrac{1}{32}\) + \(\dfrac{1}{64}\) 

    2 x B   = 1 + \(\dfrac{1}{2}\)+ \(\dfrac{1}{4}\)  +  \(\dfrac{1}{8}\) +  \(\dfrac{1}{16}\)+ \(\dfrac{1}{32}\)

2 x B - B = 1 - \(\dfrac{1}{64}\)

           B = \(\dfrac{63}{64}\)

đặt `A= 1/2 + 1/4 + 1/8 + 1/16+ 1/32 + 1/64`

`=> 2A = 2(1/2 + 1/4 + 1/8 + 1/16+ 1/32 + 1/64)`

`2A = 1+1/2 +1/4 +1/8+1/16 +1/32`

`=>A =2A -A =1+1/2 +1/4 +1/8+1/16 +1/32-1/2-1/4-1/8-1/16-1/32 -1/64`

`A = 1-1/64 = 64/64 -1/64 =63/64`

a) (25x32) : 8           

= 25 x (4 x 8) : 8

= (25 x 4) x (8:8)

= 100 x 1

=100

b, 24 x 11 + 6 x 86 x 4 + 72

= 24 x 11 + (6 x 4) x 86 + 24 x 3

= 24 x 11 + 24 x 86 + 24 x 3

= 24 x (11+86+3)

= 24 x 100

= 2 400

\(\left(25\times32\right):8=25\times32:8=25\times\left(32:8\right)=25\times4=100\\ 24\times11+6\times86\times4+72\\ =24\times11+24\times86+24\times3\\ =24\times\left(11+86+3\right)\\ =24\times100=2400\\ 36\times5+9\times79\times4+72\times8\\ =36\times5+36\times79+36\times16\\ =36\times\left(5+79+16\right)\\ =36\times100=3600\\ \left(56\times125\right):7=56\times125:7=\left(56:7\right)\times125=8\times125=1000\)