Squares in the 50s
Square 51–59 by mixing 25 with the last digit.
= 2916
54 × 54 is a square split at 50: 2500, 200, 200 and 16.
Both middle pieces are 100 × 4, so the whole-hundred part is 100 × 29.
So add the units digit to 25, then attach its square: .
Your turn
Three to try in your head — tap what you get.
All 36 shortcuts: the Magic Tricks library.