Answer:
10100
Explanation:
1·2⁴ + 0·2³ + 1·2² + 0·2¹ + 0·2⁰ = 20
one approach to get to this number systematically is to divide by 2 and write down if you have a remainder. Write from right to left until you hit 0.
20 divided by 2 is 10, no remainder, write down 0
10 divided by 2 is 5, no remainder, write down 0
5 divided by 2 is 2, remainder 1, write down 1
2 divided by 2 is 1, no remainder, write down 0
1 divided by 2 is 0, remainder 1, write down 1
You have written down 10100.
