If 𝑋 is the set of even numbers between, but not including, zero and eight, and 𝑌 is the set of digits of the number 541, what is 𝑋 minus 𝑌?
We are told in the question that 𝑋 is the set of even numbers between, but not including, zero and eight. This means that set 𝑋 contains the numbers two, four, and six. 𝑌 is the set of digits of the number 541. This means that 𝑌 contains the elements five, four, and one. We want to work out 𝑋 minus 𝑌. And we know that this means the elements of 𝑋 that are not elements of 𝑌. The number four appears in both set 𝑋 and set 𝑌. This means that the two elements that appear in set 𝑋 but not in set 𝑌 are two and six. The correct answer is, therefore, the set two and six.