Glossarytaught in M0.03, CN2.01
Order of magnitude
Also called orders of magnitude, ballpark.
Knowing whether a number is in the hundreds, the thousands or the lakhs, before caring about its digits.
Most analytical errors are order-of-magnitude errors: a crore mistaken for a lakh, a million for a billion, a monthly figure annualised twice.
To catch them, state the expected magnitude aloud before computing and check units at every step. Indian and international numbering conventions collide constantly, and the crore-to-million conversion is where it usually happens.
Get the size right first. Precision can wait until afterwards.