29 SEP 2017 by ideonexus

 Roman Arithmetic

...basic Roman arithmetic is largely rather simple, even for those of us spoiled by Arabic notation. Addition is no sweat, because complex Roman numbers already use what math pros call additive notation, with numerals set beside one another to create a larger number. VI is just V plus I, after all. To add large numbers, simply pile all the letters together, arrange them in descending order, and there’s your sum. CLXVI plus CLXVI? CCLLXXVVII, or CCCXXXII. And one of the advantages of the Rom...
Folksonomies: math mathematics education
Folksonomies: math mathematics education
  1  notes
14 APR 2012 by ideonexus

 The Matter / Antimater Imbalance in the Universe

Physicists have long pondered the problem and may have an answer. It seems that just before the universe was one millisecond old, matter and antimatter annihilated each other in a sweeping extinction. But a tiny asymmetry was built into the universe so that matter dominated over antimatter by one part out of 100 billion. Why the built-in asymmetry? In the first 100 billion-billion-billionth of a second of the universe's history, particles called X particles and their antiparticles were create...
Folksonomies: physics antimatter matter
Folksonomies: physics antimatter matter
  1  notes

In less than the first second of the Universe's existence, 1/100 billionth of the matter was left over from the annihilation with antimatter.