Question

Johnny is solving the following word problem with a classmate.Elyse is 26 years younger than her mom. If Elyse’s mom is 32, how old is Elyse?The students find the solution to be 26. How could Johnny and his classmate check for reasonableness?

Answer 1

One way that Johnny and his classmate could check the reasonableness of their answer is by adding Elyse's age to the age difference between Elyse and her mom to see if it equals Elyse's mom's age.

In this case, Elyse's mom is 32 and Elyse is 26 years younger than her mom, so:

Elyse's age + age difference = Elyse's mom's age
E + 26 = 32

Solving for E, we get:

E = 32 - 26
E = 6

So Elyse is 6 years old. To check for reasonableness, we can add Elyse's age (6) to the age difference (26) to see if it equals Elyse's mom's age (32):

Elyse's age + age difference = Elyse's mom's age
6 + 26 = 32

The sum of 6 and 26 is indeed 32, which confirms that their answer is reasonable.