Where counting starts

The idea

The point where the x-axis and the y-axis intersect is called the origin O, and its coordinates are (0, 0).

The city centre

In the oldest cities of Bhārat the streets ran straight North–South and East–West, about 10 metres apart. A merchant found a shop by counting units North–South and East–West from the city centre.

The merchant stands exactly at the city centre. How many units has he counted East–West and North–South?

• 0 and 0
• 1 and 1
• 10 and 10

Find the centre

Tap or drag on the grid, or use the arrows, to move the orange point P. Watch the two numbers in P = (x, y).

The origin

The point where the x-axis and the y-axis intersect is called the origin, O. Its coordinates are (0, 0).

Every count starts from O: 0 across and 0 up. The merchant standing at the city centre has not counted anything yet.

Notes

The point where the x-axis and the y-axis meet is the origin O. Its coordinates are (0, 0).

Check yourself

Which of these points is the origin?

A point lies on both the x-axis and the y-axis. What are its coordinates?

Which sentence about the origin is true?

• A. A is not on either axis.
• B. B is on the y-axis, but not on the x-axis.
• C — correct. C is where the x-axis and the y-axis cross. That is the origin.
• D. D is on the x-axis, but not on the y-axis.
• (0, 0) — correct. Yes. Both numbers are 0. That is the origin.
• (1, 1). (1, 1) means 1 across and 1 up. It is not on either axis.
• (0, 1). (0, 1) is on the y-axis only.
• (1, 0). (1, 0) is on the x-axis only.
• It is the point where the two axes cross. — correct. Yes. The axes cross at O.
• It is the top-right corner of the grid.. The plane goes on in every direction, so it has no corner. O is where the axes cross.
• Its coordinates are (1, 1).. At O we have not moved at all: 0 across, 0 up. So (0, 0).