Hi,
Should I learn to calculate this (66*38) in my head, or is it okay to write
66*38 (40 - 2) = 2400+240 = 2640-132 = 2508.
Writing it down takes me 30 seconds. I guess it has to be reduced, but how quickly do you think that this should be solved?
Any help would be appreciated! :)
/Nils
Great, I think I can reduce the time by practicing. But is it okay to write out the calculation by hand?
of course not necessary (mental the better), but if needed it is fine. In this case I recommend to use another sheet (to leave clean your main page with the structure)
Thank you! I have been recommended that too. I do the easy and medium math exercises in my head, but I struggle to compute the hard questions in the head as there are so many numbers to remember. Do you have a youtube movie that shows how to remember the numbers while calculating?