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January 2020
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Daily Challenges

Math and Logic

Missing Multiples

Cryptograms replace digits with letters. Today's problem only involves three digits, but don't be fooled — it's not simple.

2,671 people working on this

Science and Engineering

Otherworldly Acceleration

There's a quick and easy way to measure gravity anywhere in the solar system.

Series 7 of 7 6,340 people working on this

Friday, January 24, 2020

Math and Logic

Weighty Shapes

A balanced scale stays balanced if we add or remove equal quantities from both sides. Can you solve this balance puzzle?

5,360 people working on this

Wednesday, January 22, 2020

Math and Logic

Shaded Stars

By extending the sides of regular polygons, we can create interesting star patterns. What happens when we start shading them?

7,819 people working on this

Tuesday, January 21, 2020

Science and Engineering

Rechargeable Reactions

When your car battery loses its charge, what is it actually running out of?

Series 4 of 4 7,649 people working on this

Monday, January 20, 2020

Math and Logic

Who Gets There First?

Using a formula isn't always the best way to calculate a probability. Instead, using areas of geometric figures can make things easier.

10,101 people working on this

Sunday, January 19, 2020

Science and Engineering

Time Flies When You Turn Around

Your twin took a trip through the stars and came back younger than you, but they think they should be older. Why are they wrong?

Series 3 of 3 8,282 people working on this

Math and Logic

Pour It Out

With only two containers of different sizes, you might be surprised at how many different amounts are possible to measure out.

13,284 people working on this

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