Technique library
Mental math tricks built for a clock.
Learn each shortcut, then use the embedded drill until the method survives time pressure.
(100 − a)(100 − b) · 60 second drill
Multiply Numbers Near 100 Fast
Learn and drill the base 100 multiplication shortcut.
Symmetric offsets · 60 second drill
Square Two Digit Numbers Fast
Practice symmetric offsets for rapid two digit squares.
High frequency fractions · typed recall
Fraction to Decimal Flashcards for Quant Tests
Build instant recall for common sixths, eighths, twelfths, and sixteenths.
Double then shift · 60 seconds
Divide by 5 Fast in Your Head
Double then divide by ten with a focused timed drill.
Percent changes · timed recall
Calculate Percent Change Fast
Practice reference value selection and exact decimal shifts.
Nearby squares · rapid estimates
Estimate Square Roots Mentally
Use nearby perfect squares to estimate roots quickly.