Kilometres

In your book, Maths Mela (Chapter 5, Far and Near), we measure long distances. People use tools like a long tape, a measuring wheel (the book calls it a 'Rodometer'), a rangefinder or a laser distance meter.

When we walk 1,000 m, we say we have walked 1 kilometre, written 1 km. So 1 km = 1,000 m. 'Kilo' stands for thousand. We use kilometres for long distances, like the distance between two towns.

The book asks: how many ropes of the same length are needed to make 1 km? One rope of 1,000 m is enough. Ropes of 500 m: 500 + 500 = 1,000, so 2 ropes. Ropes of 250 m: 250 + 250 + 250 + 250 = 1,000, so 4 ropes. Ropes of 200 m: 5 ropes, because 5 × 200 = 1,000. Ropes of 100 m: 10 ropes. Ropes of 10 m: 100 ropes.

Notice that the shorter the rope, the more ropes we need to make the same 1 km.