Write an equation based on the problem in the terms of x and solve the equation
first number + second number + third number = 240
x + x + 1 + x + 2 = 240
3x + 3 = 240
3x = 240 - 3
3x = 237
x = 237/3
x = 79
The smallest number, x, is equal to 79
Find the next two numbers
the second number = x + 1
the second number = 79 + 1
the second number = 80
the third number = x + 2
the third number = 79 + 2
the third number = 81
ANSWER: The three numbers are 79, 80, 81