Fifteen less than twice a number is 21.
What is the missing number? |

2y - 15

Step-by-step explanation:

well 15 LESS than TWICE a number. okay so let’s start off by making a variable for the unknown number y. the variable is y. so now we have to think, TWICE that number, but we don’t know the number.

Now that we have the variable and we know it has to be doubled, let’s start off making the first half... we can out that into 2y. which is 2 multiplied by the unknown number.

now that we have the first half done, we have to take the 15 less. Less can mean  or subtract in this kind of situation. but for this certain scenario, it will be subtraction. so the equation would be 2y - 15.

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