the sum of 7.2 and a number is 10. first, write an equation to describe the situation.

Explanation:

Step1: Define the unknown number

Let the number be $x$.

Step2: Write the equation based on the problem

The sum of 7.2 and $x$ is written as $7.2 + x$, and it is equal to 10. So the equation is $7.2+x = 10$.

Answer:

$7.2+x = 10$