/***************************************/ /* Simple Fraction Calculator */ /* Copyright MathExpression.com */ /* http://www.mathexpression.com */ /* By Ng Wei Chong */ /***************************************/ //globals var N1, N2, D1, D2, OP; var resultNumer, resultDenom; var szTable = new Array(10); var nTableCount = 0; var isNegative = new Boolean(false); function startCalc() { //clear the alert message; document.getElementById('alertMessage').innerHTML =''; //ensure only numbers are entered if(isNaN(document.fractionCalc.N1.value) || isNaN(document.fractionCalc.D1.value) || isNaN(document.fractionCalc.N2.value) || isNaN(document.fractionCalc.D2.value)) { document.getElementById('alertMessage').innerHTML ='*Please enter numbers only'; return; } //make sure no fields are left blank if(document.fractionCalc.N1.value == '' || document.fractionCalc.D1.value == '' || document.fractionCalc.N2.value == '' || document.fractionCalc.D2.value == '' ) { document.getElementById('alertMessage').innerHTML ='*Please enter numbers into the empty box(s)'; return; } //make sure no fields are > 0 or !=0 if(document.fractionCalc.N1.value < 0 || document.fractionCalc.N2.value < 0) { document.getElementById('alertMessage').innerHTML ='*The numerators can only accept numbers from 0 - 99'; return; } if(document.fractionCalc.D1.value <= 0 || document.fractionCalc.D2.value <= 0) { document.getElementById('alertMessage').innerHTML ='*The denominators can only accept numbers from 1 - 99'; return; } //clear the alert message; document.getElementById('alertMessage').innerHTML =''; //init szTable[0]= szTable[1] = szTable[2] = szTable[3] = szTable[4] = szTable[5] = szTable[6] = szTable[7] = szTable[8] = szTable[9] = ''; nTableCount = 0; isNegative = false; //Now get the numbers N1 = document.fractionCalc.N1.value; N2 = document.fractionCalc.N2.value; D1 = document.fractionCalc.D1.value; D2 = document.fractionCalc.D2.value; OP = document.fractionCalc.OP.value; //alert(OP); switch(OP) {//sw case '+': AddFractions(); break; case '-': SubtractFractions(); break; case '*': MultiplyFractions(); break; case '/': DivideFractions(); break; }//sw } function AddFractions() { if(D1 == D2) { resultNumer = (N1*1) + (N2*1); resultDenom = D1*1; szTable[nTableCount] = '
' + N1 + '+' + N2 + '
Click here to learn the basics behind adding fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = '
= ' + N1 + ' + ' + N2 + ' Same denominators. Hence, add the numerators and keep the denominator the same.
' + D1 + '
'; nTableCount++; szTable[nTableCount] = '
=' + resultNumer + '  
' + D1 +' 
'; nTableCount++; } if(D1 != D2) { resultNumer = (N1*D2) + (N2*D1); resultDenom = D1*D2; szTable[nTableCount] = '
' + N1 + '+' + N2 + '
Click here to learn the basics behind adding fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = ' \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
= '+ N1 + '×'+ D2 + '+ '+ N2 +' ×' + D1 + 'Different denominators, use the ideas behind Equivalent Fractions to make them the same
' + D1 + '×'+ D2 + '' + D2 + '×'+ D1 + '
' nTableCount++; szTable[nTableCount] = '
=' + (N1*D2) + '+' + (N2*D1) + 'The denominators are now the same
' + (D1*D2) + '' + (D1*D2) + '
'; nTableCount++; szTable[nTableCount] = '
= ' + (N1*D2) + ' + ' + (N2*D1) + ' Hence, we can just add the numerators and keep the denominator the same
' + (D1*D2) + '
'; nTableCount++; szTable[nTableCount] = '
=' + resultNumer + '  
' + resultDenom +' 
'; nTableCount++; } //alert(nTableCount); SimplifyFraction(); UpdateDocument(); } function SubtractFractions() { if(D1 == D2) { resultNumer = (N1*1) - (N2*1); resultDenom = D1*1; if(resultNumer <0) { isNegative = true; resultNumer = Math.abs(resultNumer); } szTable[nTableCount] = '
' + N1 + '-' + N2 + '
Click here to learn the basics behind subtracting fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = '
= ' + N1 + ' - ' + N2 + ' Same denominators. Hence, add the numerators and keep the denominator the same.
' + D1 + '
'; nTableCount++; szTable[nTableCount] = '
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + Math.abs(resultNumer) + '  
' + D1 +' 
'; nTableCount++; } if(D1 != D2) { resultNumer = (N1*D2) - (N2*D1); resultDenom = D1*D2; if(resultNumer <0) { isNegative = true; resultNumer = Math.abs(resultNumer); } szTable[nTableCount] = '
' + N1 + '-' + N2 + '
Click here to learn the basics behind subtracting fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = ' \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
= '+ N1 + '×'+ D2 + '- '+ N2 +' ×' + D1 + 'Different denominators, use the ideas behind Equivalent Fractions to make them the same
' + D1 + '×'+ D2 + '' + D2 + '×'+ D1 + '
' nTableCount++; szTable[nTableCount] = '
=' + (N1*D2) + '-' + (N2*D1) + 'The denominators are now the same
' + (D1*D2) + '' + (D1*D2) + '
'; nTableCount++; szTable[nTableCount] = '
= ' + (N1*D2) + ' - ' + (N2*D1) + ' Hence, we can just minus the numerators and keep the denominator the same
' + (D1*D2) + '
'; nTableCount++; szTable[nTableCount] = '
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + resultNumer + '  
' + resultDenom +' 
'; nTableCount++; } //alert(nTableCount); SimplifyFraction(); UpdateDocument(); } function MultiplyFractions() { resultNumer = (N1*N2); resultDenom = (D1*D2); szTable[nTableCount] = '
' + N1 + '×' + N2 + '
Click here to learn the basics behind multiplying fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = ' \ \ \ \ \ \ \ \ \
='+ N1 + '×' + N2 +'Multiply the numerators together and multiply the denominators together.
' + D1 + '×' + D2 + '
' nTableCount++; szTable[nTableCount] = '
=' + resultNumer + '  
' + resultDenom +' 
'; nTableCount++; //alert(nTableCount); SimplifyFraction(); UpdateDocument(); } function DivideFractions() { resultNumer = (N1*D2); resultDenom = (D1*N2); szTable[nTableCount] = '
' + N1 + '÷' + N2 + '
Click here to learn the basics behind dividing fractions
' + D1 + '' + D2 + '
'; nTableCount++; szTable[nTableCount] = '
=' + N1 + '×' + D2 + 'Change the division to multiplication by swapping the numerator and denominator of the divisor
' + D1 + '' + N2 + '
'; nTableCount++; szTable[nTableCount] = ' \ \ \ \ \ \ \ \ \
='+ N1 + '×' + D2 +'Multiply the numerators together and multiply the denominators together.
' + D1 + '×' + N2 + '
' nTableCount++; szTable[nTableCount] = '
=' + resultNumer + '  
' + resultDenom +' 
'; nTableCount++; //alert(nTableCount); SimplifyFraction(); UpdateDocument(); } function GetFactor(nNumer,nDenom) { //Find the largest common factors var nFactor = 1; nNumber = Math.abs(nNumer); nDenom = Math.abs(nDenom); for (var nCount = 2; nCount <= Math.min(nNumer,nDenom); nCount++) {//for var TestA = nNumer/nCount; if (TestA == Math.round( TestA )) {//if1 var TestB = nDenom/nCount; if (TestB == Math.round( TestB )) {//if2 nFactor = nCount; }//if2 }//if1 }//for return nFactor; } function SimplifyFraction() { if( ((resultNumer >= resultDenom) && (resultNumer%resultDenom == 0)) || (resultNumer == 0)) { var nWholeNum = resultNumer/resultDenom; szTable[nTableCount] = '
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + nWholeNum + '
'; nTableCount++; } else {//else var lFactor = GetFactor(resultNumer,resultDenom); if(lFactor > 1) {// szTable[nTableCount] = '
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + resultNumer + '÷'+ lFactor + 'We can simplify this fraction by dividing the numerator and denominator with ' + lFactor +'
' + resultDenom + '÷' + lFactor + '
'; nTableCount++; //divide with the common factor resultNumer = resultNumer/lFactor; resultDenom = resultDenom/lFactor; szTable[nTableCount] = '
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + resultNumer + ' '+ (szTemp=(resultNumer>resultDenom)? 'This is an improper fraction. Rather than leaving it like this, it is better to convert it into a mixed fraction':' ') + '
' + resultDenom +' 
'; nTableCount++; } if( (resultNumer >= resultDenom) && (resultNumer%resultDenom != 0) ) {// var nNum = (resultNumer - resultNumer%resultDenom)/resultDenom; //the whole number resultNumer =resultNumer%resultDenom; //remainder szTable[nTableCount] = ' \ \ \ \ \ \ \ \ \ \
'+ (szTemp=(isNegative==true)?'=-':'=') +'' + nNum + '' + resultNumer + ' 
' + resultDenom + '
' nTableCount++; }// }//else } function UpdateDocument() { var szTableName; for(var nCount = 1; nCount <= nTableCount; nCount++) { szTableName = 'TableStep' + nCount; //alert(szTableName); document.getElementById(szTableName).innerHTML = szTable[nCount-1]; } for(var nCount = nTableCount; nCount <10; nCount++) { szTableName = 'TableStep' + (nCount + 1); //alert(szTableName); document.getElementById(szTableName).innerHTML = ''; } //set the message; document.getElementById('alertMessage').innerHTML ='*See the solution and answer below...'; } function AutoGenerate() { document.fractionCalc.N1.value = Math.ceil(Math.random()*20); document.fractionCalc.N2.value = Math.ceil(Math.random()*20); document.fractionCalc.D1.value = Math.ceil(Math.random()*20); document.fractionCalc.D2.value = Math.ceil(Math.random()*20); /* var OpValue = Math.floor(Math.random()*4);; switch (OpValue) { case 0: document.fractionCalc.OP.value = '+'; break; case 1: document.fractionCalc.OP.value ='-'; break; case 2: document.fractionCalc.OP.value = '*'; break; case 3: document.fractionCalc.OP.value = '/'; break; } */ //set the message; document.getElementById('alertMessage').innerHTML =''; } function ClearBoxes() { document.fractionCalc.N1.value = ''; document.fractionCalc.N2.value = ''; document.fractionCalc.D1.value = ''; document.fractionCalc.D2.value = ''; //set the message; document.getElementById('alertMessage').innerHTML =''; }