Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Newer
Older
100644 51 lines (48 sloc) 2.276 kb
9e59905 Marcia Lee Add exercise -- multiplying decimals
marcia authored
1 <!DOCTYPE html>
2 <html data-require="math math-format">
3 <head>
4e4cb9b Ben Eater lint: tabs->spaces and jQuery->$ for exercises
beneater authored
4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
5 <title>Adding and subtracting fractions</title>
6 <script src="../khan-exercise.js"></script>
9e59905 Marcia Lee Add exercise -- multiplying decimals
marcia authored
7 </head>
8 <body>
4e4cb9b Ben Eater lint: tabs->spaces and jQuery->$ for exercises
beneater authored
9 <div class="exercise">
10 <div class="vars" data-ensure="D1 !== D2">
11 <var id="N1">randRangeNonZero( -9, 9 )</var>
12 <var id="N2">randRangeNonZero( -9, 9 )</var>
13 <var id="D1">randRangeExclude( 2, 9, [ N1, -N1 ] )</var>
14 <var id="D2">randRangeExclude( 2, 9, [ N2, -N2 ] )</var>
15 <var id="LCM">getLCM( D1, D2 )</var>
16 <var id="F1">LCM / D1</var>
17 <var id="F2">LCM / D2</var>
18 </div>
9e59905 Marcia Lee Add exercise -- multiplying decimals
marcia authored
19
4e4cb9b Ben Eater lint: tabs->spaces and jQuery->$ for exercises
beneater authored
20 <div class="problems">
21 <div>
22 <div class="question">
23 <p><code><var>fraction( N1, D1 )</var> + <var>fraction( N2, D2 )</var> = {?}</code></p>
24 </div>
25 <div class="solution" data-type="rational"><var>N1 / D1 + N2 / D2</var></div>
26 </div>
27 </div>
9e59905 Marcia Lee Add exercise -- multiplying decimals
marcia authored
28
4e4cb9b Ben Eater lint: tabs->spaces and jQuery->$ for exercises
beneater authored
29 <div class="hints">
30 <p>First, we need to find a common denominator. The least common multiple of <code><var>D1</var></code> and <code><var>D2</var></code> is the smallest possible common denominator.</p>
31 <p><code>\lcm(<var>D1</var>, <var>D2</var>) = <var>LCM</var></code></p>
32 <p>Now, we need to change both fractions to have a denominator of <code><var>LCM</var></code>.</p>
33 <p><code>\begin{align*}<var>fraction( N1, D1 )</var>\cdot <var>fraction( F1, F1 )</var> &= <var>fraction( N1 * F1, LCM )</var>\\
34 <var>fraction( N2, D2 )</var>\cdot <var>fraction( F2, F2 )</var> &= <var>fraction( N2 * F2, LCM )</var>\end{align*}</code></p>
35 <div>
36 <p>So, the problem becomes:</p>
37 <p><code><var>fraction( N1 * F1, LCM )</var> + <var>fraction( N2 * F2, LCM )</var> = {?}</code></p>
38 </div>
39 <div>
40 <p><var>N2 &gt; 0 ? "Add" : "Subtract"</var> the numerators.</p>
41 <p><code><var>fraction( F1 * N1 + F2 * N2, LCM)</var></code></p>
42 </div>
43 <div data-if="getGCD( F1 * N1 + F2 * N2, LCM ) !== 1">
44 <p>Simplify.</p>
45 <p><code><var>fractionReduce( F1 * N1 + F2 * N2, LCM )</var></code></p>
46 </div>
47 </div>
48 </div>
9e59905 Marcia Lee Add exercise -- multiplying decimals
marcia authored
49 </body>
50 </html>
Something went wrong with that request. Please try again.