NCERT Solutions Ganita Prakash (Part 1) Chapter 3 .4 II. The Mayan Number System — In-text Questions
Book page 763 Updated on2026-09-05
Q1.
Represent the following numbers using the Mayan system: (i) 77 (ii) 100 (iii) 361 (iv) 721
Answer
The Mayan landmark numbers are 1, 20, 360, 7200, 144000 — note that the third is 20 × 18 = 360, not 400. A dot is 1, a bar is 5, and a shell is 0. The sets of symbols are written one below the other, with the lowest set counting the 1s, the next the 20s, the next the 360s.
Each numeral is read from the bottom up: the lowest set counts 1s, the next counts 20s, the next counts 360s. The orange shell is the Mayan placeholder for 0.
Why it happens: in (iii) and (iv) the shell is doing real work. Without it, 361 would be a dot, a gap and a dot — and no reader could tell how wide the gap was meant to be. That is the same trouble the Mesopotamians had, and the Maya solved it independently, on the other side of the world.
Did you know? Because the third landmark is 360 and not 400, this is almost but not quite a base-20 system. That is why the chapter says it lacks the computing advantages of a true base: 20 × 20 = 400 is not a landmark number, so landmark × landmark is not always a landmark. Scholars think 360 was chosen to suit the Mayan calendar.