Seemingly Simple Math

What is the answer to this math problem:

8 ÷ 2 (2 + 2)

16 or 1, depending.

According to PEMDAS, parentheses come first: 8 ÷ 2 (4)

Then, even though multiplication is first in PEMDAS, you go left to right: 4 (4) = 16

If you got 1, you’re in good company. That’s what I got at first too but most calculators I’ve tried get 16.

I found this at Popular Mechanics and the debate continues online.

Posted in Brain Teasers

Lighter Than a Feather

I’m lighter than a feather but even the world’s strongest man can’t hold me for more than a few minutes. What am I?

Breath. Air is light, but even Stig Severinsen, the world record holder can only hold his breath for 22 minutes. The world’s strongest man can’t beat that, but you can have the pleasure of telling him to his face.

Posted in Riddles

The 22nd and 24th Presidents of the U.S.

The 22nd and 24th presidents of the United States of America had the same parents, but were not brothers. How is this possible?

It was the same guy! Grover Cleveland is the only president in history to serve two, non-consecutive terms.

Posted in Brain Teasers

A Seed of Three Letters

I am a seed, three letters in the name,
Take away two and I sound quite the same.

What am I?

Pea.

Posted in Riddles

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.

Posted in Brain Teasers

The Start Of What You Might Conceive

I’m the start of whatever you might conceive.
Next I describe a Thanksgiving meal.
Last I transform to a state we all leave.

What am I?

begin, binge, being. Everything has a beginning, Thanksgiving dinner is known for being a meal of excessive consumption and the mortal state of being (or the state of a human being) is one which, for all our efforts to extend, will eventually end.

Posted in Riddles

What Kind of Nut Has a Hole?

What kind of a nut has a hole?

A donut (or a nut as in a nut and bolt). Here’s a fun fact. Another riddle with donut as the answer is, “What has no beginning, end or middle?”

Posted in Riddles

Name That Song

James makes a bet with Laura that he can use any name she can think of in a song she will recognize with the original lyrics. Laura takes him up on the bet and loses. What song did James sing to win?

Happy Birthday. When you sing Happy Birthday, you say the person’s name as part of the song.

Posted in Brain Teasers

Snake Coiled Round and Round

Snake coiled round and round,
Snake deep below the ground,
Snake that’s never had a head,
Snake that binds but not with dread.

A rope.

Posted in Riddles

A Seemingly Simple Math Problem

What is the answer to this problem?

1 + 1 + 1 + 1 + 1
1 + 1 + 1 + 1 + 1
1 + 1 × 0 + 1 = ?

30.

There are two tricks to this one. The first is 1 × 0. But it’s mostly there as a distraction. Yes, 1 × 0 is 0, but that doesn’t affect anything else in the equation. The second, far trickier element is that the lines ending with 1 don’t have a + sign next to them. That means they should be combined with the following line.

Let’s put the equation all on one line, shall we?

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 × 0 + 1 = ?

And the answer to that equation is 30.

Posted in Brain Teasers