The easiest way to solve this problem is by using cross multiplication. First we need to determine how many green lizards there are and then add this to the number of blue lizards to get the total amount of lizards. Therefore,

 (approx.) amount of green lizards

The easiest way to approximate this part of the problem is to notice that 6 is very close to 7. So if , . So if we are dividing by a slightly smaller number we will get a larger answer.

We then need to add this number to 350 blue lizards in order to get the total amount of lizards. Therefore, .

First, divide the 18oz of root beer by 6 parts in order to determine how many ounces per 1 part of root beer. Therefore, .

In order to determine the amount of ice cream, multiply 1 part (3 oz) by 3, since ice cream is comprised of 3 parts. Therefore, there are 9oz of ice cream. Add this to the 18oz of root beer in order to get the total ounces of the root beer float.

.

In number form, eight hundred seventy-nine and one hundred sixty-nine thousandths is . The "and" signifies the decimal, and "thousandths" signifies the place value of the last decimal number. 

When we write a number in expanded form, we multiply each digit by its place value. 

 is in the ones place, so we multiply by . 

 is in the tenths place, so we multiply by . 

 is in the hundredths place, so we multiply by .

Then we add the products together. 

When we write a number in expanded form, we multiply each digit by its place value. 

 is in the tens place, so we multiply by .

 is in the ones place, so we multiply by . 

 is in the tenths place, so we multiply by . 

 is in the hundredths place, so we multiply by .

Then we add the products together. 

It will take her 30 more minutes to finish her walk for a total of 45 minutes.  45 minutes of 60 minutes in an hour is the same as .

The factors of 12 are 1, 12, 3, 4, 2, and 6.  The sum of them is when you add all of them together. .

If  are male, then  of the children in the class are female .  

If this is true, then  times the total number of students in the class will give you the number of females.  

The best way to think about this problem is to divide the total number of people into parts. Since there are 5 parts women to 3 parts men, it's best to divide the total into 8 parts.  Dividing 56 into 8 parts gives you 7.  7 is your multiplier.  Now take your multiplier (7) and multiply it by your ratios.  

This give you  and  or  and .  These are the number of women and men, respectively.  

The difference between 35 and 21 is 14.

We can solve this problem by backsolving, meaning plugging in the answer choices. 

If we plug in 7 for the dog's age, that means that in 3 years, the dog will be 10. 

That also means that the cat is 3 since the dog is 4 years older. 

The sum of 10 and 3 is 13, so the answer choice of 7 is the correct answer.