Question

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Answer 1

Answer:

when they all will be multiplied the unit digit must be zero(0)

Step-by-step explanation:

See its simple

1(2)(3)(4)........(10)........(20)............(30)...............(39)

I have heighlighted numbers ending with 0.

i.e.

when they all will be multiplied the unit digit must be zero(0).

for example:

let 1(2)(3)(4).....................9= x

and

11(12)(13).....................(39)= y

So required product is

x×(10)×y

i.e.

xy(10)

clearly the number ends with zero.

hope you understand..