Indian vs International Number System

The Story

Ms. Rao drew a place-value table on the board: Ones, Tens, Hundreds, Thousands, Ten Thousands, Lakhs, Ten Lakhs, and so on.

"A period is a group of place values," she said. "In the Indian system we read in three main periods: thousands, lakhs, and crores. Commas show where each period begins."

She wrote digits into the table: 5 in lakhs, 2 in ten lakhs, 7 in thousands, 8 in ten thousands, 6 in hundreds, 4 in tens, 1 in ones.

"Read it aloud," she said. Anaya tried: "Fifty-two lakh, seventy-eight thousand, six hundred forty-one."

Ms. Rao added commas: 52,78,641. "After the ones period take three digits, then comma. In thousands take two digits, then comma. In lakhs take two digits, then comma if more periods follow."

Kabir tried the next example: 8,24,05,936. "Eight crore, twenty-four lakh, five thousand, nine hundred thirty-six."

Then 40,30,80,207: "Forty crore, thirty lakh, eighty thousand, two hundred seven."

Anaya's cousin Veer wrote the same digits the International way — commas every three from the right: 403,080,207. Same digits, different grouping names, but the stadium seat count had never changed.

"Periods are for reading and writing," said Ms. Rao. "The digits stay fixed. Only the commas and the words we use to read them change with the system."