Distinct Digit Fraction Sums
Observe the following fraction addition carefully:
1 6
--- + --- = 1
4 8
On the left side of the equation there are four distinct digits — 1, 4, 6, and 8. While that may not look like earth-shattering news to some people, I think it looks nice.
Can you make up a similar example?
This means, can you find another equation of the form
a c
--- + --- = 1
b d
where a, b, c, and d are distinct digits?
You know, it may not be as easy as it looks. This shall be called a Type I expression.
Now, how about another variation on that theme? Observe this structure…
a c e
--- + --- = ---
b d f
where a, b, c, d, e, and f are distinct digits, and e/f < 1.
Can you find a solution to that?
This shall be called Type II.
Want to go for more? Well, then look at this.
a d
---- + --- = 1
bc e
where “bc” represents a “two-digit number” (like 27 or 83), and not the algebraic multiplication of 2 values.
This shall be called Type III.
Hey, I’m not done yet. Try your luck, er skill, on this one.
ab e
---- + --- = 1
cd f
where again “ab” and “cd” represent “two-digit numbers” (like 14 or 65), and not the algebraic multiplication of 2 values.
This shall be called Type IV.
If you can show me an answer to any of these questions, send it to me by email and I will present it here on this page in the charts below.
Please note: that in order for your solution to even be considered for posting, you must write “DDFS” in the subject line of your email; otherwise I will merely ignore it and delete it. Thank you.
trottermath@gmail.com or ttrotter3@yahoo.com
For an important UPDATE, see below Chart IV…
Type I
| # | Solution | Name | Date |
| 1 | 1/4 + 6/8 | Daniel Lu | 4/30/01 |
| 2 | 1/2 + 3/6 | Konstantin Knop | 8/9/01 |
| 3 | 1/3 + 4/6 | Jacqueline Hu | 10/24/01 |
| 4 | 3/4 + 2/8 | Jacqueline Hu | 10/24/01 |
| 5 | 1/2 + 4/8 | Leonard Lee | 11/4/01 |
| 6 | 2/4 + 3/6 | Leonard Lee | 11/4/01 |
| 7 | |||
| 8 |
Type II
| # | Solution | Name | Date |
| 1 | 1/4 + 2/8 = 3/6 | Konstantin Knop | 8/9/01 |
| 2 | 3/9 + 1/6 = 2/4 | Leonard Lee | 11/4/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
Type III
| # | Solution | Name | Date |
| 1 | 2/10 + 4/5 | Konstantin Knop | 8/9/01 |
| 2 | 2/16 + 7/8 | Jacqueline Hu | 10/24/01 |
| 3 | 2/14 + 6/7 | Jacqueline Hu | 10/24/01 |
| 4 | 8/14 + 3/7 | Jacqueline Hu | 10/24/01 |
| 5 | 5/10 + 4/8 | Leonard Lee | 11/4/01 |
| 6 | 4/12 + 6/9 | Leonard Lee | 11/4/01 |
| 7 | 5/20 + 6/8 | Leonard Lee | 11/4/01 |
| 8 | 7/21 + 6/9 | Leonard Lee | 11/4/01 |
| 9 | |||
| 10 | |||
| 11 | |||
| 12 |
Type IV
| # | Solution | Name | Date |
| 1 | 13/26 + 4/8 | Konstantin Knop | 8/9/01 |
| 2 | 15/30 + 2/4 | Leonard Lee | 11/4/01 |
| 3 | 15/30 + 4/8 | Leonard Lee | 11/4/01 |
| 4 | 15/60 + 3/4 | Leonard Lee | 11/4/01 |
| 5 | 19/38 + 2/4 | Leonard Lee | 11/4/01 |
| 6 | 16/48 + 2/3 | Leonard Lee | 11/4/01 |
| 7 | |||
| 8 | |||
| 9 | |||
| 10 |
Here is Type V.
ab e
----- + --- = 1
cde f
Type V
| # | Solution | Name | Date |
| 1 | 34/102 + 6/9 | Konstantin Knop | 8/9/01 |
| 2 | 26/130 + 4/5 | Konstantin Knop | 8/9/01 |
| 3 | 35/140 + 6/8 | Leonard Lee | 11/4/01 |
| 4 | 72/108 + 3/9 | Leonard Lee | 11/4/01 |
| 5 | 53/106 + 2/4 | Leonard Lee | 11/4/01 |
| 6 | 78/156 + 2/4 | Leonard Lee | 11/4/01 |
| 7 | |||
| 8 | |||
| 9 | |||
| 10 |
Next is Type VI.
ab f
----- + ---- = 1
cde gh
Type VI
| # | Solution | Name | Date |
| 1 | 64/208 + 9/13 | Konstantin Knop | 8/9/01 |
| 2 | 85/136 + 9/24 | Konstantin Knop | 8/9/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
And now Type VII.
ab fg
----- + ---- = 1
cde hi
Type VII
| # | Solution | Name | Date |
| 1 | 24/136 + 70/85 | Konstantin Knop | 8/9/01 |
| 2 | 96/324 + 57/81 | Konstantin Knop | 8/9/01 |
| 3 | 45/180 + 27/36 | Leonard Lee | 11/4/01 |
| 4 | |||
| 5 | |||
| 6 |
This is Type VIII.
abc gh
----- + ----- = 1
def ij
Type VIII
| # | Solution | Name | Date |
| 1 | 148/296 + 35/70 | Konstantin Knop | 8/9/01 |
| 2 | 204/867 + 39/51 | Konstantin Knop | 8/9/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
This is Type IX.
ab fg
----- + ----- = 1
cde hij
Type IX
| # | Solution | Name | Date |
| 1 | 57/204 + 98/136 | Konstantin Knop | 8/9/01 |
| 2 | 59/236 + 78/104 | Konstantin Knop | 8/9/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
We like Type X.
abcd i
------ + --- = 1
efgh j
Type X
| # | Solution | Name | Date |
| 1 | 1278/6390 + 4/5 | Konstantin Knop | 8/10/01 |
| 2 | 1485/2970 + 3/6 | Konstantin Knop | 8/10/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
August 12, 2001…
Let’s continue our patterns. Here’s another variation on Type II.
a c e
--- + --- + --- = 1
b d f
Type XI
| # | Solution | Name | Date |
| 1 | 1/4 + 2/8 + 3/6 | Leonard Lee | 11/4/01 |
| 2 | 3/9 + 1/6 + 2/4 | Leonard Lee | 11/4/01 |
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |

