42 x 3 + 18 x 32 + 18 x 61

= 6 x 7 x 3 + 18 x 32 + 18 x 61

= 18 x 7 + 18 x 32 + 18  x 61

= 18 x (7 + 32 + 61)

= 18 x 100

= 1800

\(42\times3+18\times32+18\times61\)

\(=6\times7\times3+18\times32+18\times61\)

\(=18\times7+18\times32+18\times61\)

\(=18\times\left(7+32+61\right)\)

\(=18\times100\)

\(=1800\)

6 x 7 x 3 + 18 x 32 +18 x 61

18 x 7 + 18 x32 +18 x 61

18 x ( 7 + 32 + 61 )

18 x           100

1800

=9/4x2/3+16/9x4/3

=18/12+64/36

=54/36+64/36=118/36=59/18

 36/16 x 12/18 + 32/18 x 24/18 

\(=\dfrac{9}{4}\times\dfrac{2}{3}+\dfrac{16}{9}\times\dfrac{4}{3}\)

\(=\dfrac{3}{2}+\dfrac{64}{27}\)

\(=\dfrac{209}{54}\)

4 x 18 x 25

= 18 x (4 x 25)

= 10 x 100 = 1800

142 x 12 + 42 x 18

= 142 x (12 +18)

= 142 x 30 = 4260

`@` `\text {Ans}`

`\downarrow`

`69 \times 36 - 38 \times 18`

`= 69 \times 2 \times 18 - 38 \times 18`

`= 18 \times (69 \times 2 - 38)`

`= 18 \times (138 - 38)`

`= 18 \times 100`

`=1800`

=18(69*2-38)

=18*100=1800

= ( 18 : 9) x 50

= 2 x 50

= 100

\(\left(50\times18\right):9\\ 50\times18:9\\ =50\times\left(18:9\right)\\ =50\times2\\ =100\)

(50 x 18) : 9 

= (18 : 9 ) x 50

= 2 x 50

= 100

=2020

2020

=2020

a) 142 x 12 + 42 x 18

= 142 x (12 +18)

= 142 x 30 = 4260

b) 49 x 365 - 39 x 365

= (49-39) x 365

= 10 x 365 = 3650

c) 4 x 18 x 25

= 18 x (4 x 25)

= 10 x 100 = 1800

( 18 x 83 + 9 x 17 x 2 - 3 x 60 x 6 ) : 72 = ( 18 x 83 + 18 x 17 - 18 x 60 ) : 72

                                                               = [ 18 x ( 83 + 17 - 60 ) ] : 72

                                                               = ( 18 x 40 ) : 72

                                                               = 720 : 72

                                                               = 10

(18.83+9.2.17-3.6.60):72

=(18.83+18.17-18.60):72

=18.(83+17-60):72

=18.40:72

=720:72

=10