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Start your free trial###### Kai Aldag

Courses Plus Student 13,560 Points# how to run a ruby program

hey guys,

so for the extra credit in the math badge it says make a program that asks the user for input 2 numbers then add them together. anyways i build i version of it and i can't get it to run, it says that undefined method 'math' in calculator (noMethodError). anyways here's my code.

```
class Calculator
def math
print "please enter the first number"
number1 = gets
print "please enter the secound number"
number2 = gets
answer = #{number1} + #{number2}
puts = "#{answer}"
end
end
Calculator.math
```

please help, thanks, Kai.

## 1 Answer

###### Ethan Lowry

Courses Plus Student 7,323 PointsTry:

```
calc = Calculator.new
calc.math
```

Unless you specifically define a method as a **class** method, that method should be called on an individual *instance* of the class, not the class itself.

###### Kai Aldag

Courses Plus Student 13,560 Pointsok thank you, and second i now can't get it to run, i can input my 2 number but then the program ends i modified my code so here it is

```
class Calculator
def math
print "please enter the first number"
number1 = gets
print "#{number1}"
print "please enter the secound number"
number2 = gets
print "#{number2}"
answer = #{number1} + #{number2}
print = "#{answer}"
end
end
calc = Calculator.new
calc.math
```

###### Ethan Lowry

Courses Plus Student 7,323 PointsThe line where you are trying to assign your answer variable is wrong - you only use the hash symbols like that when using string interpolation a.k.a. inserting variable values within strings.

What you want to do there is simply:

```
answer = number1 + number2
puts answer
```

Note that you may also have to convert your numbers to integers (whole numbers) or floats (decimal numbers) using to_i or to_f respectively, since you can't perform math operations on strings.

As a final note, similar to what I said above, the use of string interpolation is unnecessary on all of the lines where you are simply printing the value of a variable without any other string content. You should simply put this instead:

```
puts number1
```

Hope that all helps.

###### Kai Aldag

Courses Plus Student 13,560 Pointsok thanks a lot but now i have one more issue, when i run the program it outputs the first number then the second, they're not not being added together. once again here's my code.

```
class Calculator
def math
print "please enter the first number"
number1 = gets
puts number1
print "please enter the secound number"
number2 = gets
puts number2
answer = number1 + number2
puts answer
end
end
calc = Calculator.new
calc.math
```

thanks, once again, for the help Ethan Lowry

###### Ethan Lowry

Courses Plus Student 7,323 PointsYou might need to convert your variables from strings to numbers as I mentioned before. What happens if you instead do the following:

```
answer = number1.to_i + number2.to_i
```

Where "to_i" converts a string to an *integer*. If you're using numbers with decimal spaces then use to_f for converting to *float* instead.

###### Kai Aldag

Courses Plus Student 13,560 Pointswow thanks so much it works like a charm.

thanks for the help, Kai.

## Ethan Lowry

Courses Plus Student 7,323 Points## Ethan Lowry

Courses Plus Student 7,323 PointsYou might need to convert your variables from strings to numbers as I mentioned before. What happens if you instead do the following:

`answer = number1.to_i + number2.to_i`

Where "to_i" converts a string to an

integer. If you're using numbers with decimal spaces then use to_f for converting tofloatinstead.