To determine which whole number is on the left of the other number on the number line, we need to understand that in a number line, numbers increase from left to right. This means that a smaller number will always be positioned to the left of a larger number.
For instance, consider the pair of numbers 2 and 5. On the number line, 2 is positioned to the left of 5 because 2 is less than 5. Likewise, if we look at the pair -3 and 1, the whole number -3 will be on the left of 1 since -3 is a smaller (or more negative) number than 1.
Therefore, in any given pair, simply compare the two numbers: the smaller number is always going to be the one on the left. This principle applies regardless of whether the numbers are positive or negative. To summarize, always remember: on a number line, less means left!