(from the article `number game`) Another type of number pleasantry concerns multigrades; i.e., identities between the sums of two sets of numbers and the sums of their squares or ...
Found on
http://www.britannica.com/eb/a-z/m/136
Sets of equations in which the sums of powers of two different sets of numbers are the same for several different exponents. The simplest example is: 1 + 6 + 8 = 2 + 4 + 9 1
2 + 6
2 + 8
2 = 2
2 + 4
2&l...
Found on http://www.daviddarling.info/encyclopedia/M/multigrade.html
Photographic B&W paper that provides all the different grades of contrast from one box. Invented by Ilford in the 1950's, but versions are now manufactured by all the major makers. (see Contrast grade paper)
Found on https://www.encyclo.co.uk/local/20176
No exact match found.
