Explain why do a value of a digit depends on its place value?

Answer 1

In the base ten counting system, the place value denotes a certain power of 10. The ones place, just to the left of the decimal, is 100, aka 1. The tens place, to the left of the ones place, is 101, the hundreds place is 102, and so on.

The placement of a digit essentially multiplies it by the place value, so a 7 in the hundreds place is 7*102 or 700.

Looking at a number such as 2046, we know that the two is in the thousands place, 103, so it has a value of 2000, the 4 is in the tens place, so it has a value of 40, and the six is in the ones place so it has a value of 6.

Adding up the all the products of each digit with its place value gives us a number's total value. 2000 + 40 + 6 equals 2046.