Let's go through your homework step by step:

1. Fraction Operations:

a. $\frac{3}{10} + \frac{1}{100}$
To add fractions, you need a common denominator. The least common denominator (LCD) for 10 and 100 is 100.
Rewrite $\frac{3}{10}$ as $\frac{30}{100}$, so:
$\frac{30}{100} + \frac{1}{100} = \frac{31}{100}$

b. $\frac{1}{4} - \frac{1}{100}$
The LCD for 4 and 100 is 100.
Rewrite $\frac{1}{4}$ as $\frac{25}{100}$, so:
$\frac{25}{100} - \frac{1}{100} = \frac{24}{100} = \frac{6}{25}$

c. $\frac{9}{18} \div \frac{6}{100}$
Division of fractions is done by multiplying the first fraction by the reciprocal of the second fraction:
$\frac{9}{18} \div \frac{6}{100} = \frac{9}{18} \times \frac{100}{6} = \frac{9 \times 100}{18 \times 6} = \frac{900}{108} = \frac{25}{3}$

d. $\frac{36}{100} \times \frac{7}{10}$
To multiply fractions, multiply the numerators and denominators:
$\frac{36}{100} \times \frac{7}{10} = \frac{36 \times 7}{100 \times 10} = \frac{252}{1000} = \frac{63}{250}$

2. Division Problems:

a. $29 \div 2$
$29 \div 2 = 14.5$

b. $52 \div 3$
$52 \div 3 = 17.33 \, (\text{rounded to two decimal places})$

c. $6.6 \div 4$
$6.6 \div 4 = 1.65$

d. $26 \div 8$
$26 \div 8 = 3.25$

3. Currency Exchange:

Priya's family exchanged 250 dollars for 4,250 pesos. To find out how much Priya's sweater (510 pesos) costs in dollars, we use the exchange rate: $\frac{4,250}{250} = 17 \, \text{pesos per dollar}$

Now divide the sweater cost by this exchange rate: $510 \div 17 = 30 \, \text{dollars}$

4. Quarts and Gallons:

a. How many gallons are equal to 12 quarts?
There are 4 quarts in a gallon, so divide:
$12 \div 4 = 3 \, \text{gallons}$

b. How many quarts are in 12 gallons?
Multiply the number of gallons by 4:
$12 \times 4 = 48 \, \text{quarts}$

5. Milliliters and Gallons:

a. How many milliliters are in 3 gallons?
There are 3,785 milliliters in 1 gallon. So for 3 gallons:
$3 \times 3,785 = 11,355 \, \text{milliliters}$

b. How many milliliters are in 1 quart?
There are 4 quarts in a gallon, so divide the number of milliliters in a gallon by 4:
$3,785 \div 4 = 946.25 \, \text{milliliters}$

Let me know if you'd like more details or have any questions!

Here are 5 related questions you might want to try:

1. What is $\frac{7}{8} + \frac{3}{16}$?
2. Divide $56.7 \div 9$ and round to two decimal places.
3. If Priya's sweater had cost 620 pesos, how much would it be in dollars?
4. How many quarts are in 5.5 gallons?
5. Convert 10 quarts to milliliters.

Tip: When working with fractions, always simplify them when possible to make calculations easier!