Largest Product

Using all the digits from 1 to 7, what two numbers have the largest product? For example, 1234 x 567 = 699678 but you can do much better than that.

742 x 6531 = 4,846,002.

A similar problem can be found in L.A. Graham’s Ingenious Mathematical Problems and Methods with a range of 1 to 9, but the principle remains the same – the numbers with the smallest difference produce the largest product. You start out with the highest two digits, 7 and 6, then attach 5 and 4, putting the smaller of the two digits with the larger number, giving you 74 and 65. The next two highest digits are 3 and 2, giving you 742 and 653. Finally, you add the 1 to the lower number. Page 80 has the details of that solution.

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Look at My Face

If you look at my face you won’t see 13 in any place. What am I?

A clock face. It only has the numbers 1 through 12.

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Five Letters and People Eat Me

I have five letters and people eat me. When you remove my first letter I become a crime. Remove my first two letters and I am an animal. If you remove my first and last letters I’m a form of music.

What am I?

Grape

Grape = a fruit people eat
rape = a crime
ape = an animal
rap = a category of music

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What Runs Around the Yard

What runs around the yard without moving?

A fence.

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Walks on Graves at Night

This walks on graves at night yet in homes during the day,
Men are scared of it, women like it, children play with it,
It lives on dates and salt,
It is covered in hair,
Its name starts with ‘M’ and it is mentioned in the Quran.

What is it?

Moths.
Most species of moths are nocturnal, yet they are attracted to light and can be found in homes. Men, in the most generic sense, can be scared of moths (see Mottephobia) as well as the damage they can cause as pests to bee hives, grain, flour, trees and agriculture. Women like moths because of the silk they produce. Children frequently chase and play with moths. Moths are attracted to salt and love to eat rotting fruit (such as dates). Some species of moths are densely covered with tiny hairs and of course it starts with the letter ‘m’. Lastly, moths are mentioned in the Quran (101:4 (Asad) [It will occur] on the Day when men will be like moths swarming in confusion)

Posted in Riddles

The Ants Go Marching

Three ants are walking in the same direction. The first ant has two ants behind him, the second ant has one in front and one behind, but the third ant has one in front and one behind too. How is this possible?

The ants are in a circle. Lets say the ants are A, B and C. A has has B and C behind him, B has A in front and C behind, and C has B in front and A behind.

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Mental Calculations

Perform this calculation in your head, mentally adding the numbers as quickly as you can. Start with 1000 and add 40. Now add 1000. Add 30 to that, then add another 1000. Now add 20 to that result. Add another 1000 and finally, add 10 to that. What is the total?

4,100. If you got 5,000 you’re not alone. 96% of test subjects get the wrong answer.

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Take Away All My Letters

Take away my first letter,
Take away my second letter,
Take away all my letters,
and I remain the same.

What am I?

A mail carrier. Even when there aren’t any letters left to deliver, they’re job is still the mail carrier.

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One Way I’m Feeling Normal

One way I’m feeling normal,
Another I’m extremely thin,
I could be a punishment,
Or the type who always wins.

I’m free from all impurity,
And you may have divined,
I have a keen edge,
But of course I am refined.

Fine.

The riddle refers to a variety of meanings of the word fine.

Feeling normal refers to when you feel fine.
Extremely thin refers to a fine thread.
A punishment refers to being charged a fee.
The one who wins refers to an athlete who is physically trained and hardened close to the limit of efficiency.
Free from impurity refers to measuring the fineness of precious metals.
A keen edge refers to a knife with a fine edge.
Refined refers to fine manners or elegance.

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What is HIJKLMNO?

HIJKLMNO

What 5-letter word does this represent?

Water. Or literally, H to O, which sounds the same as H2O.

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