Answer:
125 sweets
Explanation:
Let the total # of sweets the teacher bought be the variable, x.
We can set up this equation to find the # of sweets she bought:
40 · 3 + 5 = x
Because she gave 3 sweets each to her 40 students, we have to multiply these two numbers to get the # of sweets the teacher gave out.
120 + 5 = x
Then, since there's 5 extra sweets left, we can add it to the # of sweets the teacher gave out to get the total amount of sweets she bought.
125 = x
x = 125
125 sweets