Express the following number in standard form:
`3,90,878`

Answer

To express the number 390,878 in standard form, we follow these steps:

### Step 1: Identify the first non-zero digit
The first non-zero digit in the number 390,878 is 3.

### Step 2: Place the decimal point
We place the decimal point after the first digit (3), which gives us 3.90878.

### Step 3: Count the number of places the decimal point has moved
We need to count how many places we moved the decimal point from its original position (at the end of the number) to its new position (after the 3).
- The original number is 390,878, which can be thought of as 390878.0.
- The decimal point moves 5 places to the left to get to 3.90878.

### Step 4: Write the number in standard form
Now, we can express the number in standard form. We write it as:
\[ 3.90878 \times 10^5 \]

### Final Answer
Thus, the standard form of 390,878 is:
\[ 3.90878 \times 10^5 \]

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