A number line is a visual tool that represents numbers in order. Positive numbers are to the right of zero, and negative numbers are to the left of zero. Zero is the reference point that separates positive and negative numbers.
To plot negative four, we start at zero and move four units to the left. We count: negative one, negative two, negative three, negative four. We place a red dot at negative four and label it.
To plot positive five, we start at zero and move five units to the right. We count: one, two, three, four, five. We place a blue dot at five and label it.
Now we compare negative four and five on the number line. Numbers increase in value as we move from left to right. Since five is positioned to the right of negative four, five is greater than negative four. We write this as five is greater than negative four.
Any positive number is always greater than any negative number. This is because positive numbers represent values above zero while negative numbers represent values below zero. For example, in terms of temperature, five degrees Celsius is warmer than negative four degrees Celsius. In elevation, five feet above sea level is higher than four feet below sea level.