MainActivity.java

public class MainActivity extends AppCompatActivity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        TextView textView = (TextView)findViewById(R.id.textView); //idは自分のレイアウトに合わせて変更

        EditText editText1 = (EditText)findViewById(R.id.editText1);
        EditText editText2 = (EditText)findViewById(R.id.editText2);
        Button button = (Button)findViewById(R.id.Button);

        button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    String str1 = editText1.getText().toString();
                    String str2 = editText2.getText().toString();

                    int people = Integer.valueOf(str1);
                    int money = Integer.valueOf(str2);

                    int result = money / people;

                    String result_str = String.valueOf(result)
                    textView.setText(result_str);
                }
            });
    }
}