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Mathematics Goes to the Movies

by Burkard Polster and Marty Ross

**In the Navy (1941)**

Smokey Adams (Bud Abbott) is a baker on a big battleship and his friend Pomeroy Watson (Lou Costello) a handyman.

1:06:04

Costello shows Abbott in three different ways that 7 times 13 equals 28.

ABBOTT: Hey, doghnuts!

COSTELLO: No, Smokey! Don’t!

ABBOTT: Oh, come on. One doughnut.

COSTELLO: I haven’t got enough. I can’t afford it. I just baked
28 of these things. Well, after all there are 7 officers I’ve got to feed
and I’ve just got enough to give them---13 apiece.

Abbot asks Costello to prove to him that 7 times thirteen is twenty-eight. Here
is Costello’s argument (minus nonessential dialogue)

1st proof (by bogus division).

COSTELLO: There were 7 officers. There’s a 7. Now I’m going to divide
to prove it to you. Now, 28 doughnuts. (writes 7 and 28 and a blackboard) Now,
7 into 2. You couldn’t even push that big 7 into that little 2. Therefore
we can’t use the 2. I’m gonna let Dizzi hold it. … I’ll
use it later. Now, 7 into 8…. One (writes down a 1). …

Now, we’re gonna carry the 7. It’s getting’ a little heavy,
so I’ll put it right down there.

7 from eight. … 1.

Now, a minute ago, we didn’t use the 2. I’m gonna use it now. Dizzy,
give me back the 2. Thanks. Put it right down there.

Now 7 into 21?

ABBOTT: Three times.

COSTELLO: 7…. 28… 13.

ABBOTT: Now wait a minute!

2nd way (by bogus multiplication).

ABBOTT: Put down 13 up there. Now you claim that each officer gets 13 doughnuts?
Put down 7, draw a line. Now 7 times 13 is what?

COSTELLO: 28

ABBOTT: Prove it.

COSTELLO: 7 times 3?

ABBOTT: 21.

COSTELLO: 7 times 1

ABBOTT: 7

COSTELLO: 7 and 1?

ABBOTT: 1.

COSTELLO: Two.

ABBOTT: Two.

ABBOTT: Oh no. Come on.

3rd way

ABBOTT: We add this up. Put down 13 seven times.

Now we’re getting it. You claim all this added up amounts to what?

COSTELLO: 28.

ABBOTT: Adding up the 3s from the bottom to the top: 3, 6, 9, 12, 15, 18, 21

COSTELLO: Just keeps adding the 7 1s from the top to the bottom: 22, 23, 24,
25, 26, 27, 28!