Which one of the following expressions does not belong with the others? Is it (A) five multiplied by six, (B) eight multiplied by 𝑥, (C) five divided by five, (D) three multiplied by three, or (E) seven plus four?
All five of our expressions contain an operation. Options (A), (B), and (D) contain a multiplication sign. (C) contains a division sign and (E) an addition sign. We can calculate the answer to expression (A) as five multiplied by six is equal to 30. The same is true of option (C). Five divided by five is equal to one. In option (D), three multiplied by three is equal to nine. And in option (E), seven plus four is equal to 11.
Unlike the other four options, option (B) contains a variable, the letter 𝑥. Whilst eight multiplied by 𝑥 can be simplified to eight 𝑥, we don’t know its numerical value. In fact, it has an infinite number of values as we could substitute any number in for 𝑥.
The expressions (A), (C), (D), and (E) all have one value, whereas option (B) contains a variable. This means that this expression does not belong with the others or is the odd one out. The correct answer is eight multiplied by 𝑥.