To find the increase in the world's population from 1500 CE to 2020, we subtract the population in 1500 CE from the population in 2020.
World population in 1500 CE: \(4.5 \times 10^8\)
World population in 2020: \(7.8 \times 10^9\)
Now, we perform the subtraction:
\[ 7.8 \times 10^9 - 4.5 \times 10^8 \]
To subtract these numbers, it's helpful to express them with the same exponent. \(4.5 \times 10^8\) can be written as \(0.45 \times 10^9\) (which is \(4.5 \times 10^8\) multiplied by \(10^{1}\) to adjust the exponent).
Now we can set up the subtraction:
\[ 7.8 \times 10^9 - 0.45 \times 10^9 = (7.8 - 0.45) \times 10^9 \]
Calculating \(7.8 - 0.45\):
\[ 7.8 - 0.45 = 7.35 \]
Now, we can write it as:
\[ 7.35 \times 10^9 \]
So, the increase in the world's population is:
7.35×10^9 (or 7.35 times 10 superscript 9 baseline).