(6) ABACUS

ABACUS

•  Abacus the earlier and simplest device use for calculation was abacus.
• It was the first machine calculating invented in 3000 b c by Chine’s.
• Abacus a Day board with certain numbers of beats problem.
• The next manual calculating device logarithm was invented by John Napier in 1617.
• The use of logarithm enable   due to transform multiplication and division into addition, subtraction problem.
• Log abs      =   log^a+log^b.
• Log a/b      =   log^a -log^b.
• You also invited bones card with solve multiplication problem.