Unable to execute dex: Multiple dex files define Eclipse Android

Try two way in Eclipse IDE:

1.) Import the library project into your Eclipse workspace.
Click File > Import,
select Android > Existing Android Code into Workspace, and browse to the copy of the library project to import it.
If project not visible with checkbox try next step as see below.

2.) Click
File > New > Other
select Android > Existing Android Code into Workspace, and browse to the copy of the library project to import it.

Shortcut
Windows
Ctrl + Alt + L (format selection or all page)
Ctrl + Alt + Shift + L (show a dialog)
Linux
Ctrl + Windows Key + Alt + L

From menu Code
Code > Reformat Code

putString(), putBoolean(), putInt() etc.¨
How we can start an activity programmatically.

// MainActivity.java
//  myButton.setOnClickListener
Intent binary = new Intent(getApplicationContext(),Calculate.class);
	Bundle b = new Bundle();
	b.putString("prvni_label", "Decimal");
	b.putString("druhy_label", "Binary");
	b.putString("mode", "binary_to_decimal");
        binary.putExtras(b);
	startActivityForResult(binary, 0);
						
// in Calculate.java onCreate

   TextView mTextView1 = (TextView)findViewById(R.id.textView1);
   TextView mTextView2 = (TextView)findViewById(R.id.textView2);    
     Bundle _bundle = getIntent().getExtras();
		mTextView1.setText(_bundle.getString("prvni_label"));
		mTextView2.setText(_bundle.getString("druhy_label"));

//.................. HOW OPEN START NEW ACTIVITY WITHOUT A PARAMETER .........................

startActivity(new Intent(ThisActivity.this, NewActivity.class));

I tried this Eclipse and work fine:
Eclipse Classic
//www.filehippo.com/download_eclipse_classic_32/

Eclipse Juno
Eclipse Helios

//developer.android.com/tools/sdk/eclipse-adt.html

Android development
Java float is 32 bit single precision type and used when fractional precision calculation is required.

Java float je 32 bitů veliké číslo sloužící především pro přesný výsledek za desetinnou tečkou například při dělení čísel. Pro větší přesnost použíijte 64 bitový typ Double.

		// declaration and assignment of value  type float
		float x = 18.41785f;
		//print formated  value
		System.out.printf("The value of x is %.3f%n", x); // 18.418
                
                // declaring more variables in single statement
                float f1 = 12.4F, f2 = 564.5F, f3 = 14.589F;

		// float range of value
		System.out.println(Float.MIN_VALUE); // 4E-45
		System.out.println(Float.MAX_VALUE); // 4028235E38

		// is NaN  Not-a-Number
		float f = (float) Math.sqrt(-15);
		boolean bNaN = Float.isNaN(f);
		System.out.print(bNaN); // true
		
                // check if a string is a valid number in Java example
                // convert string to float Java example
		String sF = "12.8";
		float fParse = Float.parseFloat(sF);

	       // convert strings to numbers
	      String sFl = "15.48";
	      float fFromString = (Float.valueOf(sFl)).floatValue();

// float to string in Java example code
Float fObj = new Float(68.5);
String str = fObj.toString();
// else 
Float fS = 11.6f;
String sFloat = fS.toString();

              // compare two float variables
	      Float fComp1 = 4.3f;
	      if(fComp1.equals(4.3f))
	  		System.out.print("true");

	    // compares the two specified float values in Java example
	    int i =	Float.compare(11.5f, 11.7f); // -1 first < second
	    // 0 first == second
	    // 1 first > second
	    System.out.print(i);