According to a survey conducted in 2007, there were an estimated 6.99 × 107 dogs, 3.61 × 107 cats, and 8.3 × 106 birds kept as pets in the United States. In this activity, you’ll add these three numbers in both standard form and in scientific notation and check whether you get the same sum. First, add the numbers using standard form. Convert each of the three pet populations to standard form.