CUBE

Cubes of large numbers are rarely used. Here we are going to practice two-digit number..

First we have remember the cubes up to 10

1³ = 1               2³= 8                3³= 27              4³= 64              5³= 125                                   

6³= 216            7³= 343            8³= 512            9³= 729            10³= 1000

If two digit number starts with 1 like 11 12 13 14 15 16 17 18 19 to calculate the cubes of these

Ex 1.    12³ =

Step I:             1 2 4 8 (double the previous ones)

              ( 2x2=4 and 4x2=8)

Step II:              4 8           (Step I middle numbers multiply with 2)

                        (2x2=4 and 4x2=8)

ADD Step I and Step II

                        1 2 4 8

                           4 8   

                        __________

                        1 7 2 8 answer

Ex 2.    16³ =

Step I:             1   6   36   216 (double the previous ones)

                (6x6=36 and 36x6=216)

Step II:               12   72          (Step I middle numbers multiply with 2)

                        (6x2=12 and 36x2=72)

ADD Step I and Step II

                       

                1          6          36       216

                                    12        72                                 

                        _____________________

                        4          30         129       216       = 4096 answer

(36+72+21=129   6+12+12=30)

Try all up to 11 to 19