diff --git a/src/app/components/results/BinaryStringView.jsx b/src/app/components/results/BinaryStringView.jsx
index 0d38784..1ddb58b 100644
--- a/src/app/components/results/BinaryStringView.jsx
+++ b/src/app/components/results/BinaryStringView.jsx
@@ -11,7 +11,7 @@ export default class BinaryStringView extends React.Component {
         }
 
         if(this.props.onFlipBit) {
-            this.props.onFlipBit(index);
+            this.props.onFlipBit({ index: index, binaryString: this.props.binaryString, $event: e });
         }
     }
 
@@ -29,7 +29,6 @@ export default class BinaryStringView extends React.Component {
         const allowFlipBits = this.props.allowFlipBits || false;
         const css = allowFlipBits ? ' flipable' : ''
         const classNames = { '0': `zero${css}`, '1' : `one ${css}` };
-        
         return bitChars.map((c, i) => <span className={classNames[c]} key={i} onClick={e => this.onBitClick(i, e)}>{c}</span>);
     }
 
diff --git a/src/app/components/results/BitwiseOperationExpressionView.jsx b/src/app/components/results/BitwiseOperationExpressionView.jsx
index cb6ce6e..5dd4d1f 100644
--- a/src/app/components/results/BitwiseOperationExpressionView.jsx
+++ b/src/app/components/results/BitwiseOperationExpressionView.jsx
@@ -1,5 +1,5 @@
 import React from 'react';
-import * as expression from '../../expression';
+import { Operand, ListOfNumbersExpression, SingleOperandExpression, MultipleOperandsExpression } from '../../expression';
 import formatter from '../../formatter';
 import BinaryStringView from './BinaryStringView';
 import BitwiseExpressionViewModel from './models/BitwiseExpressionViewModel';
@@ -23,17 +23,17 @@ export default class BitwiseOperationEpxressionView extends React.Component {
         const expr = this.props.expression;
         var model = null;
 
-        if(expr instanceof expression.ListOfNumbersExpression) {
+        if(expr instanceof ListOfNumbersExpression) {
             model = BitwiseExpressionViewModel.buildListOfNumbers(expr, { 
                 emphasizeBytes: this.props.emphasizeBytes, 
                 allowFlipBits: true });
         }
 
-        if(expr instanceof expression.SingleOperandExpression) {
+        if(expr instanceof SingleOperandExpression) {
             model = BitwiseExpressionViewModel.buildNot(expr, { emphasizeBytes: this.props.emphasizeBytes });
         }
 
-        if(expr instanceof expression.MultipleOperandsExpression) {
+        if(expr instanceof MultipleOperandsExpression) {
             model = BitwiseExpressionViewModel.buildMultiple(expr, { emphasizeBytes: this.props.emphasizeBytes });
         }
 
@@ -48,7 +48,7 @@ class ExpressionRow extends React.Component {
        this.state = { operand: null };
    }
     render() {
-        const { sign, label, bin, other, css, maxNumberOfBits, emphasizeBytes, allowFlipBits, operand } = this.props;
+        const { sign, css, maxNumberOfBits, emphasizeBytes, allowFlipBits, operand } = this.props;
         
         return <tr className={css}>
                     <td className="sign">{sign}</td>
@@ -56,28 +56,31 @@ class ExpressionRow extends React.Component {
                     <td className="bin">
                         <BinaryStringView 
                             emphasizeBytes={emphasizeBytes} 
-                            binaryString={formatter.padLeft(operand.bin, maxNumberOfBits, '0')} 
+                            binaryString={formatter.padLeft(operand.toBinaryString(), maxNumberOfBits, '0')} 
                             allowFlipBits={allowFlipBits} 
                             onFlipBit={idx => this.flipBit(idx)}/>
                     </td>
-                    <td className="other">{operand.other}</td>
-                </tr>;
+                    <td className="other">{this.getOther(operand)}</td>
+                </tr>;;
     }
 
     getLabel(op) {
-        return op.kind == 'bin' ? op.dec : op.toString();
+        return op.toString(op.kind == 'bin' ? 'dec' : op.kind);
     }
 
-     flipBit(index) {    
+    getOther(op) {
+        return op.toString(op.getOtherKind());
+    }
 
-        var op = this.props.operand;
-        const binaryString = formatter.padLeft(op.bin, this.props.maxNumberOfBits, '0');
+     flipBit(args) {    
+
+        const op  = this.props.operand;
+        const { index, binaryString } = args;
+        
         var arr = binaryString.split('');
-        // TODO: this code looks ugly
         arr[index] = arr[index] == '0' ? '1' : '0';
         var bin = arr.join('');
 
-        console.log('new bin: '+ bin);
         op.setValue(parseInt(bin, 2));
 
         this.setState({ operand: op });
diff --git a/src/app/components/results/models/BitwiseExpressionViewModel.js b/src/app/components/results/models/BitwiseExpressionViewModel.js
index 9fa7726..c10d9be 100644
--- a/src/app/components/results/models/BitwiseExpressionViewModel.js
+++ b/src/app/components/results/models/BitwiseExpressionViewModel.js
@@ -51,21 +51,16 @@ export default class BitwiseExpressionViewModel {
         this.maxNumberOfBits = Math.max(operand.getLengthInBits(), this.maxNumberOfBits);
         this.items.push({ 
             sign:'', 
-            label: this.getLabel(operand), 
-            bin: operand.bin, 
-            other: operand.other, 
             css: '',
-            operand: operand});
+            operand: operand
+        });
     };
 
     addExpression(expression) {
         this.maxNumberOfBits = Math.max(expression.operand1.getLengthInBits(), this.maxNumberOfBits);
         this.items.push({ 
             sign: expression.sign, 
-            label: this.getLabel(expression.operand1), 
-            bin: expression.operand1.bin, 
-            other: expression.operand1.other, 
-            css: '',
+            label: this.getLabel(expression.operand1),
             operand: expression.operand1
         });
     };
@@ -74,22 +69,18 @@ export default class BitwiseExpressionViewModel {
         this.maxNumberOfBits = Math.max(resultOperand.getLengthInBits(), this.maxNumberOfBits);
         this.items.push({
             sign: expression.sign + expression.operand1.input,
-            label: this.getLabel(resultOperand),
-            bin: resultOperand.bin,
-            other: resultOperand.other,
             css: 'expression-result',
-            operand: resultOperand});
+            operand: resultOperand
+        });
     };
 
     addExpressionResult(operand) {
         this.maxNumberOfBits = Math.max(operand.getLengthInBits(), this.maxNumberOfBits);
         this.items.push({ 
             sign:'=', 
-            label: this.getLabel(operand), 
-            bin: operand.bin, 
-            other: operand.other, 
             css: 'expression-result',
-            operand: operand});
+            operand: operand 
+        });
     };
 
     getLabel (op) {
diff --git a/src/app/expression/Operand.js b/src/app/expression/Operand.js
index 296b767..4c55a9c 100644
--- a/src/app/expression/Operand.js
+++ b/src/app/expression/Operand.js
@@ -4,17 +4,9 @@ import ExpressionError from './ExpressionError';
 // Represents numeric value
 export default class Operand {
         constructor(cfg) {
-
             this.input = cfg.input;
             this.value = cfg.value;
             this.kind = cfg.kind;
-
-            this.hex = Operand.toHexString(this.value.toString(16));
-            this.dec = this.value.toString(10);
-            // >>> 0 makes negative numbers like -1 to be displayed as '11111111111111111111111111111111' in binary instead of -1
-            this.bin = this.value < 0 ? (this.value >>> 0).toString(2) : this.value.toString(2);
-            this.other = this.kind == 'hex' ? this.dec : this.hex;
-
             this.lengthInBits = Operand.getBitLength(this.value);
         }
                 
@@ -35,17 +27,29 @@ export default class Operand {
             }
     };
 
-    toString() {
-        return this.input;
+    toString(kind) {
+        return Operand.toKindString(this.value, kind || this.kind);
+    }
+
+    toOtherKindString() {
+        return this.toString(this.getOtherKind());
+    }
+
+    toDecimalString() {
+        return this.toString('dec');
+    }
+
+    toHexString() {
+        return this.toString('hex');
+    }
+
+    toBinaryString() {
+        return this.toString('bin');
     }
 
     setValue(value) {
         this.value = value;
-        this.bin = Operand.toKindString(this.value, 'bin');
-        this.dec = Operand.toKindString(this.value, 'dec');
-        this.hex = Operand.toKindString(this.value, 'hex');
-        this.other = Operand.toKindString(this.value, this.getOtherKind());
-        this.input = Operand.toKindString(this.value, this.kind);
+        this.input = this.toString();
     }
         
     static getBitLength(num) {
diff --git a/tests/unit/expressionSpec.js b/tests/unit/expressionSpec.js
index 96761e6..4af791a 100644
--- a/tests/unit/expressionSpec.js
+++ b/tests/unit/expressionSpec.js
@@ -94,9 +94,9 @@ describe('negative operands', function () {
     var op = parser.parseOperand('-0xa');
     it('shoold have correct values', function() {
         expect(op.value).toBe(-10);
-        expect(op.hex).toBe('-0xa');
-        expect(op.bin).toBe('11111111111111111111111111110110');
-        expect(op.dec).toBe('-10');
+        expect(op.toHexString()).toBe('-0xa');
+        expect(op.toBinaryString()).toBe('11111111111111111111111111110110');
+        expect(op.toDecimalString()).toBe('-10');
         expect(op.kind).toBe('hex');
     })
 });
@@ -129,15 +129,15 @@ function rundOperandsTest(hexOperand, decOperand) {
     it('should have all kinds', function () {
 
         expect(hexOperand.kind).toBe('hex');
-        expect(hexOperand.dec).toBe('16');
-        expect(hexOperand.bin).toBe('10000');
-        expect(hexOperand.hex).toBe('0x10');
-        expect(hexOperand.other).toBe('16');
+        expect(hexOperand.toDecimalString()).toBe('16');
+        expect(hexOperand.toBinaryString()).toBe('10000');
+        expect(hexOperand.toHexString()).toBe('0x10');
+        expect(hexOperand.toOtherKindString()).toBe('16');
 
         expect(decOperand.kind).toBe('dec');
-        expect(decOperand.dec).toBe('10');
-        expect(decOperand.bin).toBe('1010');
-        expect(decOperand.hex).toBe('0xa');
-        expect(decOperand.other).toBe('0xa');
+        expect(decOperand.toDecimalString()).toBe('10');
+        expect(decOperand.toBinaryString()).toBe('1010');
+        expect(decOperand.toHexString()).toBe('0xa');
+        expect(decOperand.toOtherKindString()).toBe('0xa');
     });
 }
\ No newline at end of file