A cube of 21cm length is cut into small cubes of side 7cm each. How much such small cubes can be obtained?

27 42 49 21

27

Volume of larger cube    = (21)3 cm3 Volume of smaller cube = (7)3 cm3 No. of such cubes          =  \(\frac{Volume\;of\;larger\;cube}{Volume\;of\;smaller\;cube}\)                                      = (\(\frac{21}{7}\))3                                      =  (3)3 = 27