What number should be multiplied by the numerator and denominator of 1/3 to make the equivalent fraction 2/6?

The number should be multiplied by 2

1x2=2. 3x2=6

There are infinite number of fractions that are equal to
1
3
.
You can multiply the numerator and denominator of
1
3
by any number and the resulting fraction would be equal to
1
3
so long as you are multiplying both by the same number.
For example:
1
3
=
1
⋅
2
3
⋅
2
=
2
6
1
3
=
1
⋅
4000
3
⋅
4000
=
4000
12000