A good way to estimate this would be rounding to the nearest whole number.
First we'll look at 4.73. If we're rounding to the nearest whole number, then that means we'll look at the digit one place to the right of 4. The digit to the right of 4 is 7. 7 is greater than 5 so we round up. We get 5. If we do the same for the other number we see that it also gets rounded up to 9. So our new equation is: 5 x 9. That is a simple multiplication equation and when we multiply we get 45.
