Supercharging the Brain: Abacus or Calculator for Maths?
One cosy afternoon, two siblings, aged 5 and 7, were playing with numbers at the dining table, when the younger one asked, "Do you want to supercharge your brain with me?" The older one, intrigued, nodded, and they both started their little game—one with a calculator, and the other with an abacus.
As part of their game, the 7-year-old typed a tricky sum into the calculator:
"5783 × 46 = ?"
With a few quick taps, the answer appeared on the screen. But be
