Answer:
As i understand this:
We have cards with the values:
0, 1, 2 and 6.
We want to create a two digit number such that:
Not all the cards are used.
6 is one digit of our number.
When we round to the nearest ten, we get 20.
Now, first remember how rounding works.
If we have a number like ab, where a and b are single digits (a is in the tens place and b is in the units place), then:
if b is 5 or more, we round up
if b is less than 5, we round down.
Now in this case we want to have a digit equal 6, if we use this in the units place, then when rounding, we will round up.
Then the other digit can be 1, such that we use the cards:
1 and 6.
then our number is 16:
When rounding, 6 > 5, then we round up to 20.
So this number meets all the conditions.