Rujukan

1.  Murugiah A/L Velayutham.Kao Thuan Keat.(2007).HBMT2103:Teaching Mathematics for Year Two.6th edition.Selangor.Meteor Doc Sdn.Bhd.

     2.   http://www.youtube.com/watch?v=VASC2aeehWc&feature=related

     3.   http://www.youtube.com/watch?v=Wl6VDFaNn10&feature=related

     4.   http://www.youtube.com/watch?v=qYtNhNP69lk&feature=related

     5.   http://www.youtube.com/watch?v=LQMa-GSgGkA&feature=related