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Also factor out subtracting_decimals
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@sophiebits
sophiebits committed Nov 18, 2011
1 parent 95d6db6 commit ad6f4a7
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43 changes: 13 additions & 30 deletions exercises/subtracting_decimals.html
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Original file line number Diff line number Diff line change
Expand Up @@ -7,48 +7,31 @@
</head>
<body>
<div class="exercise">
<div class="vars" data-ensure="NEW_A > NEW_B">
<div class="vars" data-ensure="A_FLOAT > B_FLOAT">
<var id="A">randRange( 101, 999 )</var>
<var id="B">randRange( 101, 999 )</var>

<var id="A_DECIMAL">randRange( 1, 3 )</var>
<var id="B_DECIMAL">randRange( 1, 3 )</var>
<var id="NEW_A">A * ( B_DECIMAL &gt; A_DECIMAL ? pow( 10, B_DECIMAL - A_DECIMAL ) : 1)</var>
<var id="NEW_B">B * ( A_DECIMAL &gt; B_DECIMAL ? pow( 10, A_DECIMAL - B_DECIMAL ) : 1)</var>
<var id="A_DIGITS">
(function() {
var result = digits( NEW_A );
for ( var i = 0; i &lt; ( A_DECIMAL - B_DECIMAL ) || result.length &lt; A_DECIMAL + 1; i++ ) {
result.push( 0 );
}
return result;
})()</var>
<var id="B_DIGITS">
(function() {
var result = digits( NEW_B );
for ( var i = 0; i &lt; ( B_DECIMAL - A_DECIMAL ) || result.length &lt; B_DECIMAL + 1; i++ ) {
result.push( 0 );
}
return result;
})()</var>

<var id="A_FLOAT">A / pow( 10, A_DECIMAL )</var>
<var id="B_FLOAT">B / pow( 10, B_DECIMAL )</var>
</div>

<div class="problems">
<div>
<p><code>\Huge{<var>roundTo( A_DECIMAL, A * pow( 10, -A_DECIMAL ) ).toFixed( A_DECIMAL )</var> - <var>roundTo( B_DECIMAL, B * pow( 10, -B_DECIMAL ) ).toFixed( B_DECIMAL )</var> = {?}}</code></p>
<div class="solution" data-type="decimal"><var>A * pow( 10, -A_DECIMAL ) - B * pow( 10, - B_DECIMAL )</var></div>
<div class="graphie" id="numbers">
graph.subtractor = new Subtractor( NEW_A, NEW_B, A_DIGITS, B_DIGITS );
DUMMY = Array( graph.subtractor.getNumHints() );
</div>
<p><code>\Huge{<var>A_FLOAT.toFixed( A_DECIMAL )</var> - <var>B_FLOAT.toFixed( B_DECIMAL )</var> = {?}}</code></p>
<div class="solution" data-type="decimal"><var>A_FLOAT - B_FLOAT</var></div>
</div>
</div>
<div class="hints">
<div class="graphie" data-update="numbers">
graph.subtractor.show();
graph.subtractor.showDecimals( A_DECIMAL, B_DECIMAL );
<div class="graphie" id="numbers">
graph.adder = new DecimalSubtractor( A, A_DECIMAL, B, B_DECIMAL );
graph.adder.show();
graph.adder.showDecimals();
</div>
<div class="graphie" data-update="numbers" data-each="DUMMY as dummy">
graph.subtractor.showHint();
<div class="graphie" data-update="numbers" data-each="DecimalSubtractor.numHintsFor( A, A_DECIMAL, B, B_DECIMAL ) times">
graph.adder.showHint();
</div>
</div>
</div>
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87 changes: 54 additions & 33 deletions utils/graphie-helpers-arithmetic.js
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Original file line number Diff line number Diff line change
Expand Up @@ -123,38 +123,6 @@ Adder.numHintsFor = function( a, b ) {
return KhanUtil.digits( a + b ).length + 1;
};

function DecimalAdder( a, aDecimal, b, bDecimal ) {
var newA = a * ( bDecimal > aDecimal ? Math.pow( 10, bDecimal - aDecimal ) : 1 );
var newB = b * ( aDecimal > bDecimal ? Math.pow( 10, aDecimal - bDecimal ) : 1 );

var aDigits = KhanUtil.digits( newA );
for ( var i = 0; i < ( aDecimal - bDecimal ) || aDigits.length < aDecimal + 1; i++ ) {
aDigits.push( 0 );
}

var bDigits = KhanUtil.digits( newB );
for ( var i = 0; i < ( bDecimal - aDecimal ) || bDigits.length < bDecimal + 1; i++ ) {
bDigits.push( 0 );
}

var adder = new Adder( newA, newB, aDigits, bDigits );

adder.showDecimals = (function( old ) {
return function() {
old.call( adder, aDecimal, bDecimal );
}
})( adder.showDecimals );

return adder;
}

DecimalAdder.numHintsFor = function( a, aDecimal, b, bDecimal ) {
var newA = a * ( bDecimal > aDecimal ? Math.pow( 10, bDecimal - aDecimal ) : 1 );
var newB = b * ( aDecimal > bDecimal ? Math.pow( 10, aDecimal - bDecimal ) : 1 );

return Adder.numHintsFor( newA, newB );
}

function Subtractor( a, b, digitsA, digitsB ) {
var graph = KhanUtil.currentGraph;
digitsA = digitsA || KhanUtil.digits( a );
Expand All @@ -172,7 +140,7 @@ function Subtractor( a, b, digitsA, digitsB ) {
sideY: 1.5 };

var index = 0;
var numHints = digitsA.length + 1;
var numHints = Subtractor.numHintsFor( a, b );

this.show = function() {
graph.init({
Expand Down Expand Up @@ -292,6 +260,59 @@ function Subtractor( a, b, digitsA, digitsB ) {
};
}

Subtractor.numHintsFor = function( a, b ) {
return KhanUtil.digits( a ).length + 1;
};

// convert Adder -> DecimalAdder and Subtractor -> DecimalSubtractor
(function() {
var decimate = function( drawer ) {
var news = function( a, aDecimal, b, bDecimal ) {
var newA = a * ( bDecimal > aDecimal ? Math.pow( 10, bDecimal - aDecimal ) : 1 );
var newB = b * ( aDecimal > bDecimal ? Math.pow( 10, aDecimal - bDecimal ) : 1 );
return [ newA, newB ];
};

var decimated = function( a, aDecimal, b, bDecimal ) {
var newAB = news( a, aDecimal, b, bDecimal );
var newA = newAB[0], newB = newAB[1];

var aDigits = KhanUtil.digits( newA );
for ( var i = 0; i < ( aDecimal - bDecimal ) || aDigits.length < aDecimal + 1; i++ ) {
aDigits.push( 0 );
}

var bDigits = KhanUtil.digits( newB );
for ( var i = 0; i < ( bDecimal - aDecimal ) || bDigits.length < bDecimal + 1; i++ ) {
bDigits.push( 0 );
}

var drawn = new drawer( newA, newB, aDigits, bDigits );

drawn.showDecimals = (function( old ) {
return function() {
old.call( drawn, aDecimal, bDecimal );
}
})( drawn.showDecimals );

return drawn;
};

decimated.numHintsFor = function( a, aDecimal, b, bDecimal ) {
var newAB = news( a, aDecimal, b, bDecimal );
var newA = newAB[0], newB = newAB[1];

return drawer.numHintsFor( newA, newB );
};

return decimated;
};

// I hate global variables
DecimalAdder = decimate(Adder);
DecimalSubtractor = decimate(Subtractor);
})();

function drawCircles( num, color ) {
with ( KhanUtil.currentGraph ) {
var numCols = Math.floor( Math.sqrt( num ));
Expand Down

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