Difficulty: Fun
Anamaria and Chen are two friends who toured a magical chocolate factory! They both get enormous amounts of chocolate and they want to share it evenly between them. Anamaria gets 1,574,936 squares of chocolate and Chen gets 3,569,321 squares of chocolate.
Without using a calculator, can you tell if it is possible for them to share the chocolate between them without breaking any squares?
Need a hint?
Those are some big numbers! Rather than doing big calculations, can you think of another way to work it out?
Do you know a special name for a number you can share evenly between two people?
Brainteaser answer
No, the sum of 1,574,936 and 3,569,321 is odd, so it cannot be divided evenly between the two friends.
Divided “evenly” is the key word for this problem! Even numbers, by definition, can be divided by two. Odd numbers don’t divide evenly by two – they leave a remainder of 1.
To know whether the sum of chocolate can be divided evenly, we need to find out whether the sum is even or odd. We can do this by adding the digits in the ones place for both amounts: 6 + 1 = 7, an odd number! This means the sum ends with a 7, which means it is odd (remember you can think of smaller numbers to double check this, like 27 and 107 are both definitely odd).
So, we’ve figured out that the total amount of chocolate is odd, meaning that it does not divide evenly! Chen and Anamaria will have to give the last square to someone else!
Did you know that there are predictable patterns when adding evens and odds?
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