We use comparison problems to show how one number is greater (larger) or less (smaller) than another. Let's practice reading and solving comparison problems with this example.
Nathan was visiting his grandparents for the holidays. One day he asked, "Pop-Pop, how old are you?"
Pop-Pop chuckled. "Well, I'm a lot older than you are, Nathan," he said. "But I'm 5 years younger than your grandmother!"
"How old is she?" Nathan asked.
"She's 33 years older than your father," Pop-Pop said.
Nathan scratched his head.
"And your father is 28 years older than you," Pop-Pop finished.
"I'm 12 years old," said Nathan. "So let's see . . ."
With the information Pop-Pop has given, can you figure out how old Nathan's father, grandmother, and Pop-Pop are?
Here's a hint: You can set this up as a comparison problem. Use the variable N to stand for Nathan's age, F for his father's, G for his grandmother's, and P for Pop-Pop's. What does the example tell you? Here are the facts:
P equals 5 less than G.
G equals 33 more than F.
F equals 28 more than N.
N equals 12.
Now you should be able to solve the problem. Remember that the two lesser numbers in a number family add up to equal the greatest number.
Ready to move on to the next lesson?
Addition Problems with Letters and Numbers
