Question

Tính bằng cách thuận tiện nhất :

a. 69,78 x \(\dfrac{3}{4}\) + 69,78 x \(\dfrac{1}{4}\) + 69,78 x 99

b. 34,1 x 8 + 34,1 x 0,5

Answer 1

\(a,=69,78\times\left(\dfrac{3}{4}+\dfrac{1}{4}+99\right)\\ =69,78\times\left(\dfrac{4}{4}+99\right)\\ =69,78\times\left(1+99\right)=69,78\times100=6978\\ b,34,1\times8+34,1\times0,5\\ =34,1\times\left(8+0,5\right)\\ =34,1\times8,5\\ =289,85\)

Answer 2

a: =69,78(3/4+1/4+99)

=69,78*100

=6978

b: =34,1(8+0,5)=34,1*8,5=289,85

Answer 3

a.\(69,78\times\dfrac{3}{4}+69,78\times\dfrac{1}{4}+69,78\times99=69,78\times\left(\dfrac{3}{4}+\dfrac{1}{4}+99\right)=69,78\times100=6978\)

b. \(34,1\times8+34,1\times0,5=34,1\times\left(8+0,5\right)=34,1\times8,5=289,85\)

Answer 4

a) 69,78 x \(\dfrac{3}{4}\) + 69,78 x \(\dfrac{1}{4}\) + 69,78 x 99

= 69,78 x ( \(\dfrac{3}{4}\) + \(\dfrac{1}{4}\) + 99 )

= 69,78 x       1      + 99 

= 69,78 x            100

=             6978

 

b) 34,1 x 8 + 34,1 x 0,5

= 34,1 x ( 8 + 0,5 )

= 34,1 x        8,5

=         289,85