multiplying
  乘 乘法
  Mul·ti·ply v. t. [imp. & p. p. Multiplied p. pr. & vb. n. Multiplying ]
  1. To increase in number; to make more numerous; to add quantity to.
     Impunity will multiply motives to disobedience.   --Ames.
  2. Math. To add (any given number or quantity) to itself a certain number of times; to find the product of by multiplication; thus 7 multiplied by 8 produces the number 56; to multiply two numbers. See the Note under Multiplication.
  3. To increase (the amount of gold or silver) by the arts of alchemy. [Obs.]
  Multiplying gear Mach., gear for increasing speed.
  Multiplying lens. Opt. See under Lens.