February 2019
Problem of the Month

Math Doublets

A word ladder (also known as doublets) is a word game invented by Lewis Carroll.   A word ladder puzzle begins with two words, and to solve the puzzle one must find a chain of other words to link the two, in which two adjacent words differ by one letter.   Here is an example:

Change TEN to SIX.
T E N
T I N
S I N
S I X

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Here are four math doublets proposed by Roger Robison.   You must solve three of them to get credit for this month's problem.

Change ZERO to NULL

Change ONE to TWO

Change FOUR to FIVE

Change TAN to ARC

Solution to the Problem:

Change ZERO to NULL

Z E R O
H E R O
H E L O
H E L L
H U L L
N U L L

Z E R O
H E R O
H E R E
H A R E
H A R T
H U R T
H U R L
H U L L
N U L L

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Change ONE to TWO

O N E
O D E
O D D
A D D
A I D
B I D
B A D
C A D
C O D
C O O
T O O
T W O

one/ore/ort/out/tut/tot/too/two

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Change FOUR to FIVE

F O U R
F O U L
F O I L
F A I L
F A L L
F I L L
F I L E
F I V E

four/tour/tout/toot/tool/toll/till/tile/file/five

F O U R
D O U R
D O U T (To put out)
P O U T
P O S T
P O S E
P O L E
P A L E
P A V E
G A V E
G I V E
F I V E

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Change TAN to ARC

T A N
P A N
P I N
D I N
D I M
A I M
A R M
A R C

tan/can/cat/cut/out/ort/art/arc

Correctly solved by:

1. Roger Robison   ***	San Antonio, Texas
2. Ivy Joseph	Pune, Maharashtra, India
3. SreeRoopa Sankararaman ***	Singapore, Singapore
4. Frankie Jenkins	Mountain View High School, Mountain View, Wyoming
5. Brijesh Dave ***	Mumbai City, Maharashtra, India
6. Kaylee Gross	Mountain View High School, Mountain View, Wyoming
7. Hunter Gross	Mountain View High School, Mountain View, Wyoming
8. Mairany Jaracuaro	Delta High School, Delta, Colorado
9. Alyssa Marke   ***	Delta High School, Delta, Colorado

        *** solved the extra credit

Send any comments or questions to: David Pleacher