On 17 January 2014 10:11, Rossano Gobbi wrote: > Maybe useful if you are teaching to someone who can't understand the > classic way. > Probably. And/but there are other similar ways of doing the same thing. Below "[" and "]" are unnecessary and used for 'clarity'. eg 63 x 27 =3D (60 + 3) x (20 + 7) =3D [60 x 20] + [3 x 20] + [7 x 60] + [3 x 7] =3D 100 x [6 x 2] + [3 x [2 x 10] ] + [7 x [6 x 10]] + [3 x 7] The 'complicated' adding a 0 to 6 to make it 60 then separating it again coud be omitted but has some explanatory power. =3D 12 x 100 + 6 x 10 + 42 x 10 + 21 =3D 1200 +(6 + 42) x 10 + 21 =3D 1200 + 480 + 21 =3D 1701 Obviously this could be 'much shortened' but still be more expanded than usual and help with understanding. _______________________ even 63 x 27 =3D 1200 + 60 + 420 + 21 =3D 1701 Can be 'rapidly enough arrived at once the positional depiction of powers of 10 is understood. ie 63 =3D 60+3 27 =3D 20 +7. R > > What's the name of this strange method? > > > How does it work? > > > > > > https://www.facebook.com/photo.php?v=3D1378789205699173&set=3Dvb.13743522= 92809531&type=3D2&theater > > > > It's a graphical way of showing the actions that you would do when > > performing the same calculation by other means. > > It gets messy when you get larger digits involved. > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .