standard_description: Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other. For example, estimate the population of the United States as 3 × 108 and the population of the world as 7 × 109, and determine that the world population is more than 20 times larger.
problem_activity: Task
The product of two positive numbers is 9. The reciprocal of one of
these numbers is 4 times the reciprocal of the other number. What is
the sum of the two numbers?


aligns: no