| Some of you who have small children may have perhaps been put in the |
| embarrassing position of being unable to do your childs arithmetic homework |
| because of the current revolution in mathematics |
| Hing known as the new math. so as a public service here tonight I thought I would offer a brief lesson in the new math. tonight were going to cover |
| subtraction. this is the first room Ive work |
| R a while that didnt have a blackboard so we will have to make due with more |
| primitive visual aids, as they say in the «ad biz."consider the following |
| subtraction problem, which I wi |
| T up here: 342 — 173. |
| Now remember how we used to do that. three from two is nine; carry the one, |
| and if youre under 35 or went to a private school you say seven from three is six, but if youre over 35 and went to Lic school you say eight from four is six; carry the one so we have 169, |
| but in the new approach, as you know, the important thing is to understand |
| what youre doing rather than to get the right |
| Er. heres how they do it now. |
| You cant take three from two, |
| Two is less than three, |
| So you look at the four in the tens place. |
| Now thats really four tens, |
| So you make it three tens, |
| Regroup, and you change a ten to ten ones, |
| And you add them to the two and get twelve, |
| And you take away three, thats nine. |
| Is that clear? |
| Now instead of four in the tens place |
| Youve got three, |
| cause you added one, |
| That is to say, ten, to the two, |
| But you cant take seven from three, |
| So you look in the hundreds place. |
| From the three you then use one |
| To make ten ones… |
| (and you know why four plus minus one |
| Plus ten is fourteen minus one? |
| cause addition is commutative, right.) |
| And so you have thirteen tens, |
| And you take away seven, |
| And that leaves five… |
| Well, six actually. |
| But the idea is the important thing. |
| Now go back to the hundreds place, |
| And youre left with two. |
| And you take away one from two, |
| And that leaves??? |
| Everybody get one? |
| Not bad for the first day! |
| Hooray for new math, |
| New-hoo-hoo-math, |
| It wont do you a bit of good to review math. |
| Its so simple, |
| So very simple, |
| That only a child can do it! |
| Now that actually is not the answer that I had in mind, because the book that I got this problem out of wants you to do it in base eight. but dont panic. |
| base eight is just like base ten really |
| Youre missing two fingers. shall we have a go at it? hang on. |
| You cant take three from two, |
| Two is less than three, |
| So you look at the four in the eights place. |
| Now thats really four eights, |
| So you make it three eights, |
| Regroup, and you change an eight to eight ones, |
| And you add them to the two, |
| And you get one-two base eight, |
| Which is ten base ten, |
| And you take away three, thats seven. |
| Now instead of four in the eights place |
| Youve got three, |
| cause you added one, |
| That is to say, eight, to the two, |
| But you cant take seven from three, |
| So you look at the sixty-fours. |
| «sixty-four? how did sixty-four get into it? «I hear you cry. |
| Well, sixty-four is eight squared, dont you see? |
| (well, you ask a silly question, and you get a silly answer.) |
| From the three you then use one |
| To make eight ones, |
| And you add those ones to the three, |
| And you get one-three base eight, |
| Or, in other words, |
| In base ten you have eleven, |
| And you take away seven, |
| And seven from eleven is four. |
| Now go back to the sixty-fours, |
| And youre left with two, |
| And you take away one from two, |
| And that leaves??? |
| Now, lets not always see the same hands. |
| One, thats right! |
| Whoever got one can stay after the show and clean the erasers. |
| Hooray for new math, |
| New-hoo-hoo-math, |
| It wont do you a bit of good to review math. |
| Its so simple, |
| So very simple, |
| That only a child can do it! |
| Come back tomorrow night. were gonna do fractions. |
| Now Ive often thought Id like to write a mathematics text book because I have a title that I know will sell a million copies. Ill call it tropic of calculus. |