I have more math problems that I will to figure out.

21 divided by 14.88

To solve the division problems, you can use long division to find the exact quotients.

Let's start with 3.1 divided by 4:

Step 1: Write down the division problem:
0.775 represents 3.1

_______
4 | 3.100

Step 2: Divide the first digit of the dividend (3) by the divisor (4). The quotient is 0, but since there's a decimal point in the dividend, we'll bring down a zero after the decimal point.

_______
4 | 3.100
- 0.00

Step 3: Bring down the next digit (1) and append it to the end of the partial quotient.

_______
4 | 3.100
- 0.000

Step 4: Divide the new dividend (10) by the divisor (4). The quotient is 2.

_______
4 | 3.100
- 0.775
- 0.00

So, 3.1 divided by 4 is equal to 0.775.

Now let's solve 6.4 divided by 9:

Step 1: Write down the division problem:
0.711 represents 6.4

______
9 | 6.400

Step 2: Divide the first digit of the dividend (6) by the divisor (9). The quotient is 0, but since there's a decimal point in the dividend, we'll bring down a zero after the decimal point.

______
9 | 6.400
- 0.00

Step 3: Bring down the next digit (4) and append it to the end of the partial quotient.

______
9 | 6.400
- 0.711

So, 6.4 divided by 9 is approximately equal to 0.711.

Therefore, you made a mistake in your calculation. The correct values are:
- 3.1 divided by 4 is equal to 0.775.
- 6.4 divided by 9 is approximately equal to 0.711.