There are several issues in your code,

- In C++ = stands for assignment to check value equivalency you have to use ==

```
if (choose = 1, 2, 3){
...
// this doesn't work in C/C++
// change it into
if (choose == 1 || choose == 2 || choose == 3)
```

When you have more than one line of code under a conditional (if/else or loops for/while) you will need to explicitly block them inside curly braces. So that changes if first if block into this

`if (choose == 1 || choose == 2 || choose == 3){ cout << "Insert the first value: " << endl; cin >> first; cout << "Insert the second value: " << endl; cin >> second; ...`

Same goes for the nested if condition.

Also there’s no reason to take input for start.

If you fix all the errors you should get a code like this ->

```
//CALCULATOR
#include <iostream>
using namespace std;
int main()
{
int start;
int choose;
int first;
int second;
int unic;
int result;
cout << "CALCULATOR (2 values)" << endl;
cout << "Click a botton to continue: " << endl;
// cin >> start;
cout << "Write: " << endl;
cout << "- '1' for sum" << endl;
cout << "- '2' for subtraction" << endl;
cout << "- '3' for moltiplication" << endl;
cout << "- '4' for power of 2" << endl;
cout << "Your answer: " << endl;
cin >> choose;
cout << "________________________" << endl;
if (choose == 1 || choose == 2 || choose == 3){
cout << "Insert the first value: " << endl;
cin >> first;
cout << "Insert the second value: " << endl;
cin >> second;
if (choose == 1)
result = first + second;
if (choose == 2)
result = first + second;
if (choose == 3)
result = first * second;
}
if (choose == 4){
cout << "Insert the value: " << endl;
cin >> unic;
result = unic * unic;
}
cout << "Your result is: " << result << endl;
}
```

Footnote: Please use the given code as reference and try to understand the basics carefully. It is importat you do that.

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