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Kevork Keheian

Posted on • Updated on

# Computational Thinking - Riddle 1

What two whole, positive numbers that have a one-digit answer when multiplied and a two-digit answer when added?
riddle source: http://riddles.com/

## How to?

We need to declare 2 variable `sum` and `mult`:

• `sum` is to check the sum of the 2 digits.
• `mult` is to check the multiplication of the 1 digit.

And both should be assigned as 0.

``````sum = 0
mult = 0
``````

Now we need 2 for loops to iterate through the needed numbers
The numbers should be between 1 and 9, beacuse their multiplication should be only 1 digit.
1-Any number multiplied by 0 will result 0

2-Any number less than 10 multiplied by 10 or a number greater than 10 will result to number of 2 digits

``````for x in range(1, 10):
for y in range(1, 10):
sum = x + y
mult = x * y
if(sum >= 10):
if(mult < 10):
print(str(x) + " and " + str(y))
break
``````

And finally we need to break the iteration at the end of the second loop to avoid iterating through the same numbers twice.

``````