2Digit Multiplication Lite APP
Practicing these methods is, by itself, a good brain training.
19x17
(19+7)x10 + 9x7 = 323 (Method-A1)
58x58
((5x5)+8)x100 + 8x8 = 3364 (Method-A6)
Please see the following site for how to use this app.
https://android.brain-workout.org/mathmethod/