Open-ended questions ask about the answer. The answer is unknown.  The question asks for the answer.

Open-ended questions are the basis for word problems or story problems that we will practice later in this book. Right now, let’s practice the grammar for open-ended questions with the “to-be” and “non-to be” verbs in subtraction problems.

The “To Be” Open-Ended Questions–To Be Verb “is”

For the equal sign, we can simply say “is”.

Look at the simple equation:

5 – 4 = 1  “five minus four is one”

“Is” is the 3rd-person singular word in grammar. The 3rd-person singular grammar rule is used to form questions.

For example,

5 – 4 = 1   “Is five minus four  one?”

The above question is used to double check the answer.

Sometimes, people need to ask for the answer.

The subtraction operation of “five minus four” is the singular subject. It changes places with the verb “is” used for the equal sign. The subject and verb change places, and we use the question word “what” to ask for the answer.

For example, questions that use “what”

13 – 4 = _____

The question is, “what is thirteen take away four?”

48 – 32 = _____

The question is, “what is 48 minus 32?”

Let’s continue the idea that each side of the equal sign is singular for English grammar.

For example,

23 – 10 = 13

On the left of the equal sign, the math operation of subtraction, 23 – 10, is a single operation. It is one act of subtraction.

On the right side, the answer is 13.  For English grammar, the answer is also 3rd-person singular.
This definition that both sides of the equal sign are singular means that we can use the phrase “how much” to ask about the answer of a math problem. Remember, “how much” is used for singular and non-count nouns.

In the example above, we do not know what 23 is counting.  We know, simply, that the answer is grammatically singular. The answer is a non-count noun. The correct question is:

“How much is 23 minus 10?”

Another example:

39 – 13 = _____   The question is, “How much is 39 take away 13?”

The “To Be” Open-Ended Questions–To Be Phrases

The equal sign can also be said with a variety of “is” phrases.

• is equal to
• is equivalent to

Let’s look at a couple of examples about forming questions with “is” phrases.

For example:

22 – 13 = ______

“What is 22 minus 13 equal to?”

or

“What is 22 minus 13 equivalent to?”

Another example:

96 – 79 = ______

“How much is 96 take away 79 equal to?”

or

How much is 96 subtracted by 79 equivalent to?”

We can use the question words “what” or “how much” at the beginning of the question. The word “is” moves in front of the subtraction operation. The other words in the phrase stay to the right of the subtraction operation. The “is” phrases are split into two by numbers.

The other “is” phrases use the word “same”. Remember, the following:

• is the same as
• is the same amount as
• is the same value as

Let’s look at a couple of examples of questions with the phrase “is the same as”.

52 – 26 = ______

“What is 52 minus 26 the same as?”

or

“How much is 52 minus 26 the same as?”

We can use the question words “what” or “how much” at the beginning of the question. The word “is” moves in front of the subtraction operation. The other words in the phrase stay to the right of the subtraction operation. The words in “is” phrases are separated by numbers.

All of these examples above are grammatically 3rd-person singular.  The numbers do not count anything. The operation (e.g. subtraction) and the answer are non-countable terms.

The “To Be” Open-Ended Questions–Other Verbs (not To Be)

The equal sign can also be said without using the “To Be” verb “is”.  Do you remember the other ways we can say the equal sign?

• equals
• makes

Notice the final -s at the end of both of the words “equal” and “make” used for the equal sign.  The final -s identifies the verb as a 3rd-person singular verb as we saw with the word “is”.  Let’s learn about the “equals” verb first.

“equals”

Let’s look at the equation.

7 – 4 = ______

We must use the 3rd-person singular verb grammar rule to make an open-ended question with non-to be verbs.  We begin the sentence with a question word, e.g. “what”, then use “does”, write the subtraction operation, and then drop the final -s from the word “equals”.

For example:

7 – 4 = ______   The question is, “What does seven take away seven equal“?

17 – 14 = _____   The question is, “What does 17 minus 14 equal?

The same process is true for the question phrase “how much”.

Use the question phrase “how much” then “does” at the beginning of the question. Drop the final -s from make.

For example:

7 – 4 = ______   The question is, “How much does seven take away seven equal“?

17 – 14 = _____   The question is, “How much does 17 minus 14 equal?

Let’s look at the other one-word way to say the equal sign.  It is an Other Verb (not to be).

“makes”

It follows the same 3rd-person singular grammar pattern to form a question.  Use a question word, e.g. “what” and “does” before the math operation. Drop the final -s from makes.

For example:

5 – 3 = ______   The question is, “What does five minus three make“?

23 – 19 = ____   The question is, “What does 23 take away 19 make?

The same process is true for the question phrase “how much”.

Use the question phrase “how much” then “does” at the beginning of the question. Drop the final -s from make.

For example:

5 – 3 = ______   The question is, “How much does five minus three make“?

23 – 19 = ____   The question is, “How much does 23 subtracted by 19 make?

Summary

The subtraction operation on one side of the equal sign (=) is singular.

The answer on the other side of the equal sign (=) is also singular.

The grammar for question formation uses 3rd-person singular rules for making questions that ask for the answer.