regular 2 by 2 or 2 by 3, do yall use the tricks for ending in 5, same tens....and all that. or do you follow teh same routine for multiplication each time? which one is more time efficient?
for me, it's more efficient to have just one method and use it all the time, it saves time choosing which method. for 2 by 2, i always do FOIL unless it's something extremely easy like one's digits add up to 10, or a really recognizable difference of squares.
For 2 by 2s, I FOIL 90% of the time. I use tricks for things like * 11 and * 15 and other easy things. Most 2 by 3s and 3 by 3s have specific tricks like * 143, 286 etc. or * 125, 625.
