I have ….

3 ones
15 hundredths
9 tenths
What number am I?

3.9 + .15 = ?

Oh! 18.9! Thaks! I've been working on this for about an hour! @PsyDAG

To determine the number represented by this combination of ones, hundredths, and tenths, we need to understand the place value system.

Let's break down the given information:

3 ones = 3
15 hundredths = 0.15 (since 15 hundredths = 0.15)
9 tenths = 0.9

Now, we can add these values together to find the answer:

3 + 0.15 + 0.9 = 4.05

Therefore, the number represented by this combination of ones, hundredths, and tenths is 4.05.