Tuesday 22 November 2022 is both a ‘Twosday’ and a palindromic date. Twosdays have to be on the second day of the week (Tuesday), and also have to be on either 2 or 22 of the month. And a palindrome is the same when read forwards or backwards. The name HANNAH is a palindrome, as is the date 22.11.22.
Twosdays
Tuesday 22 November is a Twosday. We have already had three such dates in 2022, which were
- Twosday 22 February 2022
- Twosday 22 March 2022
- Twosday 2 August 2022
Let’s look at those dates more carefully.
22 November 2022 can be written 22.11.22, which is a palindrome.
22 February 2022 can be written 22.02. 2022, also a palindrome. There was quite a lot of fuss about this date earlier in the year.
Of course, both examples have used a different format. It becomes even more complicated once you start including American date format!
The other two dates mentioned above, whilst ‘Twosdays’ are not actually palindromic.
What’s special about the number 2?
Primes
Did you know that 2 is the only even prime number? A prime is a number that will only divide by itself and 1. No other even numbers can be primes, as they will, by definition divide by 2.
Binary
The binary number system is based around 2. In fact, it’s also known as ‘base 2’. So just as in our decimal system, we use the numbers 0 – 9, and then move on to 10, 11 etc, in the binary system we count thus:
1 = 1
2 = 10
3 = 11
4 =100
Can you keep going?
Squares
We use the number 2 to represent the square of something. 22 = 4. Squared just means multiply something by itself.
So 32 = 9, 42 = 16….
Pronic numbers
Pronic numbers are numbers that are a product of two (yes two!) consecutive numbers. The number 2 is a pronic number because it is 1 x 2.
Another pronic number is 12, as it is 3 x 4.
Can you find any others?
In words
The number two can be found in thousands of words. When you see ‘bi’ in a word it is normally connected with the number 2. Examples are bicycle, bisect, bilingual, binary and so on.
A game with twos
Can you write the numbers 1 – 10 using only the number 2, and mathematical symbols? Here are a few examples.
1 = 2/2
6 = 2 x 2 + 2
It’s fun! Why not have a go?
And if you got to 10, can you keep going?
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