Fix commas

[StevenClontz]

See discussion in https://github.com/TeamBasedInquiryLearning/precalculus/discussions/223

[siwelwerd]

See here, one workaround is to enclose the comma in braces, e.g. $3{,}456$ gives $3{,}456$ instead of $3,456$. It seems this is a LaTeX feature where it interprets the comma as a list separator. There are some LaTeX packages that will deal with this, but I haven't found any that work with MathJax (see this 10 year old open request to implement one such package as a MathJax extension, for example).

[siwelwerd]

There are a few false positives in here, but I think this captures the remaining ones to be fixed.

(base) drew@Drews-MBP-2 precalculus % grep -n "\d,\d\d\d" source/*/*.ptx
source/03-LF/05.ptx:414:              <m>(0,32)</m> and <m>(100,212)</m>
source/03-LF/07.ptx:158:      A couple has a total household income of <m>\$104,000</m>. The wife earns <m>\$16,000</m> less than twice what the husband earns. How much does the wife earn?
source/03-LF/07.ptx:202:          <li>The wife earns <m>\$29,300</m>.</li>
source/03-LF/07.ptx:203:          <li>The wife earns <m>\$40,000</m>.</li>
source/03-LF/07.ptx:204:          <li>The wife earns <m>\$64,000</m>.</li>
source/03-LF/07.ptx:205:          <li>The wife earns <m>\$74,600</m>.</li>
source/03-LF/07.ptx:212:        C: <m>\$64,000</m>
source/03-LF/07.ptx:220:      Kenneth currently sells suits for Company A at a salary of  <m>\$22,000</m>  plus a  <m>\$10</m>  commission for each suit sold. Company B offers him a position with a salary of <m>\$28,000</m>  plus a  <m>\$4</m>  commission for each suit sold. How many suits would Kenneth need to sell for the options to be equal?
source/04-PR/02.ptx:122:          <p> When will the population of the city reach 36,000 people?
source/05-EL/01.ptx:21:        You have two job offers on the horizon.  One has offered to pay you <m>\$10,000</m> per month while the other is offering <m>\$0.01</m> the first month, <m>\$0.02</m> the second month, <m>\$0.04</m> the third month and doubles every month. Which job would you rather take? 
source/05-EL/01.ptx:27:        Make a table representing how much money you will be paid each month for the first two years from the first job - paying <m>\$10,000</m> per month. 
source/05-EL/01.ptx:46:        Job 1 is earning <m>\$10,0000</m> per month.  Job 2 is earning <m>\$40.96</m> per month.
source/05-EL/01.ptx:58:        Job 1 is earning <m>\$10,0000</m> per month.  Job 2 is earning <m>\$2621.44</m> per month.
source/05-EL/01.ptx:70:        Yes! After 20 months, Job 1 is earning <m>\$10,0000</m> per month.  Job 2 is earning <m>\$10,485.76</m> per month.
source/05-EL/06.ptx:74:          <m>\log_{10}(1,000,000)=x</m>
source/05-EL/06.ptx:77:            <li><m>100,000</m></li>
source/05-EL/07.ptx:105:              How many days does it take until <m>2,500</m> people have viewed this video?
source/05-EL/07.ptx:383:          A <m>529</m> Plan is a college-savings plan that allows relatives to invest money to pay for a child's future college tuition; the account grows tax-free. Lily currently has $<m>10,000</m> and opens a <m>529</m> account that will earn <m>6</m>% compounded semi-annually. 
source/05-EL/07.ptx:391:              <li><m>A(t)=10,000\left(1+\frac{6}{2}\right)^{2t}</m></li>
source/05-EL/07.ptx:392:              <li><m>A(t)=10,000\left(1+\frac{0.06}{2}\right)^{2t}</m></li>
source/05-EL/07.ptx:393:              <li><m>A(t)=10,000\left(1+\frac{6}{\frac{1}{2}}\right)^{\frac{1}{2}t}</m></li>
source/05-EL/07.ptx:394:              <li><m>A(t)=10,000\left(1+\frac{0.06}{2}\right)^{18}</m></li></ol>
source/05-EL/07.ptx:408:              <li>$<m>106,090</m></li>
source/05-EL/07.ptx:409:              <li>$<m>103,000</m></li>
source/05-EL/07.ptx:410:              <li>$<m>13,439</m></li>
source/05-EL/07.ptx:411:              <li>$<m>18,061</m></li></ol>
source/05-EL/07.ptx:423:            How many years will it take Lily to have $<m>40,000</m> in the account for her granddaughter? Round to the nearest tenth.
source/05-EL/07.ptx:448:            Kathy plans to purchase a car that depreciates (loses value) at a rate of <m>14</m>% per year.  The initial cost of the car is $<m>21,000</m>.  Which equation represents the value, <m>v</m>, of the car after <m>3</m> years?
source/05-EL/07.ptx:450:              <li><m>v=21,000(0.14)^3</m></li>
source/05-EL/07.ptx:451:              <li><m>v=21,000(0.86)^3</m></li>
source/05-EL/07.ptx:452:              <li><m>v=21,000(1.14)^3</m></li>
source/05-EL/07.ptx:453:              <li><m>v=21,000(0.86)(3)</m></li></ol>
source/05-EL/07.ptx:465:            Mr. Smith invested $<m>2,500</m> in a savings account that earns <m>3</m>% interest compounded annually.  He made no additional deposits or withdrawals.  Which expression can be used to determine the number of dollars in this account at the end of <m>4</m> years?
source/05-EL/07.ptx:467:              <li><m>2,500(1+0.03)^4</m></li>
source/05-EL/07.ptx:468:              <li><m>2,500(1+0.3)^4</m></li>
source/05-EL/07.ptx:469:              <li><m>2,500(1+0.04)^3</m></li>
source/05-EL/07.ptx:470:              <li><m>2,500(1+0.4)^3</m></li></ol>
source/05-EL/07.ptx:498:            A person invested $<m>1,000</m> in an account earning <m>10</m>% per year compounded continuously. How much was in the account at the end of one year?
source/05-EL/07.ptx:503:            $<m>1,105.17</m>