On an abacus, the hundreds spoke has three beads, the tens spoke has zero beads, and the ones spoke has nine beads. This means that the number represented on the abacus is 309.

Write the standard forms of:

a) 300 +20 +0

b) 400 + 10 +0

c) 200+30 +1

To solve this problem, let's first understand how an abacus represents numbers. An abacus is a counting tool that consists of vertical rods with beads that can be moved back and forth. The beads are divided into different places, representing different place values in a number.

In a standard abacus, the rightmost place represents ones, the next place represents tens, the next place represents hundreds, and so on. Each place can hold a certain number of beads.

In this problem, we are given the following information:
- The hundreds place has 3 beads
- The tens place has 0 beads (empty)
- The ones place has 9 beads



To find the number represented by this abacus, we need to consider the place values of each bead. Let's break down the calculation:

- The hundreds place has 3 beads, so we can multiply the number of beads by 100:
3 x 100 = 300

- The tens place has 0 beads, so it doesn't contribute to the number.

- The ones place has 9 beads, so we can multiply the number of beads by 1:
9 x 1 = 9

Putting it all together, the number represented by this abacus is 300 + 0 + 9 = 309.

Therefore, the number is 309.



To summarize, the abacus representation given in this problem has 3 beads in the hundreds place, 0 beads in the tens place, and 9 beads in the ones place. By considering the place values of each bead, we calculated the number to be 309.