Let's solve the following problem:
Step 1
First we draw segments that correspond to the ages of the two children.
In the problem, it is given that Megan is 11 years old and Vicky is 3 years older. For Megan's years, we draw a line and above it we write the number 11. Since Vicky is 3 years older, this means that she is Megan's age + three more years, so we draw a line for Megan's years and add one more a small segment to show 3 years more.
Step 2
We move on to the solution of the task.
The task asks what is the sum of the years of the two girls.
Solution:
We record the information that is given in the condition of the task:
M + V = ?
M = 11
V = 11 + 3
Then we replace:
M + V = ?
11 + (11 + 3) = 11 + 14 = 25
Answer: The sum of the ages of the two girls is 25
* Mathematical problems with finding an unknown number can be found in the course Competitive Mathematics - Level 3