# ISEE Middle Level Math : How to subtract variables

## Example Questions

### Example Question #27 : How To Subtract Variables

Solve.

None of these

Explanation:

The first step to solving is to convert all the numbers to a common form. We will convert to decimals, since this form is used in the answer choices.

Plug this value into the original equation and solve.

### Example Question #91 : Operations

If  is an odd number, which of the following must also be odd?

Explanation:

The easiest way to solve this problem is to pick an odd number (we can use 3 for example), and plug it into each answer choice.

The only answer choice that gives us an odd result is:

As a rule of thumb, an even number subtracted from an odd number will always result in an odd number.

### Example Question #92 : Operations

Philip had a glass containing 16 ounces of water. He drank 2 ounces. His brother then drank half of what remained. How many ounces of water are now in the glass?

Explanation:

If there were 16 ounces of water to start, this amount decreased to 14 ounces when Philip drank 2 ounces.

With 14 ounces remaining, his brother drank half. This would be equal to 7 ounces.

This left the other half of the water, which was also 7 ounces; thus, 7 ounces in the amount of water that remained.

### Example Question #93 : Operations

If  minus two times another number equals , what is the other number?

Explanation:

The first step is to transfer  minus two times another number equals  into mathematical terms. Doing so gives us:

Next, 17 is subtracted from each side.

Each side is now divided by

### Example Question #21 : How To Subtract Variables

Jim and Jack are having tea together. There are 10 sugar cubes on a small tray. Jim takes 1 cube for his tea, and Jack takes twice as many cubes as Jim. How many sugar cubes remain?

Explanation:

The first step is to convert the following into a mathematical equation:

There are 10 sugar cubes on a small tray. Jim takes 1 cube for his tea, and Jack takes twice as many cubes as Jim.

The equation for the remaining cubes would be:

Therefore, 7 is the correct answer.

### Example Question #22 : How To Subtract Variables

There are 9 cats in a shelter. Bob adopts 2 of the cats. Anita then adopts more cats than Bob adopted, but fewer than the majority of the cats remaining. How many cats did Anita adopt?

Explanation:

If Anita adopted more cats than Bob, then she adopted more than 2 cats.

Given that Bob adopted 2 cats, there are 7 cats remaining. A majority of the remaining cats would be 4.

Given that Anita adopted more than 2 cats, but less than 4, she must have adopted 3 cats; therefore, 3 is the correct answer.

### Example Question #23 : How To Subtract Variables

Tom has 8 pretzel sticks. He gives one stick to his sister, and then breaks what remains in half. Tom eats 5 of the half-pretzel sticks. How many half-pretzel sticks remain?

Explanation:

If Tom has 8 pretzel sticks and gives one stick to his sister, then he will have 7 pretzel sticks remaining. If he then breaks what remains in half, he will have 14 half-pretzel sticks. If Tom eats 5 of the half-pretzel sticks, 9 half-pretzel sticks will therefore remain.

### Example Question #712 : Concepts

Explanation:

Subtract the numbers and keep the variable:

### Example Question #24 : How To Subtract Variables

Simplify the following expression

Explanation:

Simplify the following expression

We can begin by grouping like terms:

Next, combine the like terms. In this case, simply treat them like two subtraction problems.

### Example Question #25 : How To Subtract Variables

Simplify the following: