Step One
Find the sum of the fractions for Monday and Tuesday
1/2 + 2/5
The common denominator for these 2 days is 10
1/2: 1*5/(2*5) = 5/10
2/5:2*2/(2*5) = 4/10
Add these two equivalent fractions together.
5/10 + 4/10 = 9/10
The first 2 days resulted in 9/10 of the shed being completed.
Step Two
Find out how much (in terms of fractions) is left of the shed.
Let the whole shed = 1
Let what has been done = 9/10
What remains is 1 - 9/10 = 1/10
Answer: 1/10 of the shed needs to be done
