Hullo from London! Where, to counter potential anxiety, I have made you a video of my little hot air engine... which is powered entirely by the heat of MY CUP OF TEA
How to find out if a number is a multiple of 7:
Multiply the last digit by 5 and add this to the rest of the number.
If this answer is divisible by 7, the original number is a multiple of 7.
Easy!
e.g. 532:
53 + 2x5 = 63
63 is a multiple of 7, so:
532 is a multiple of 7 😃
Shiver in ecstasy. In 1954, humanity began to hunt for integer solutions for x^3+y^3+z^3 = k, for k from 1 to 100. We finally have the solution for 42. https://t.co/t2WV13qv7H
No century begins with a Tuesday, Thursday, or Sunday
Proof: In 400 years there are 97 leap and 303 non-leap: 400x365+97=146097 days, which is divisible by 7 - everything repeats after 400 years (G.C.)! Since
1/1/2000-Saturday
1/1/2100-Friday
1/1/2200-Wednesday
1/1/2300-Monday
I've seen some data about most (and least) common birthdays doing the rounds recently, but it's clearly from the US, so here is the same data from England and Wales.
The moiré effect is an optical illusion created by parallel lines crossing over each other in the field of view; you can use this effect to make looping animations https://t.co/sAnAx1zByV [source of the gif: https://t.co/1eWxLky5zY]