How to Multiply by “9”

"Nine Months in School" lyrics

Most kids have to go to school for 9 months of every year. This multiplication song will help you calculate how many months of school it will take to graduate

Do I really have to go to the 1st grade?
Nine months of school is such a bummer
Well you need to learn how to work with numbers
If you wanna have a happy summer

1 times 9 is 9,
9 long months in school
That's too long, way too long
Why talk about it in a song (Hey!)

Do I really have to go to 2nd grade?
Nine more months of school I fear
Well you need to learn how to add and subtract
You've got to use that thing between your ears

2 times 9 is 18
18 months of school
That's too long, way too long
Why talk about it in a song (Hey!)

Do I really have to go to the 3rd grade?
Nine more months, I have to complain
Well you need to learn how to multiply
It's a fast way to add when all the numbers are the same

3 times 9 is 27
27 months of school
That's too long, way too long
Why talk about it in a song (Hey!)

Nine months!
Nine months!

To multiply any one digit number by 9
All you have to do is place a zero to its right
And then subtract your original number

(Please explain)

So 4 times 9 would become 40 - 4, which is 36
And 7 times 9 would be 70 - 7 (that would be 63)
That's right!

Do I really have to go to 4th grade?
Nine months of school is just no fair
Well you've got to learn how to do long division
That way you'll know if you got a fair share

4 times 9 is 36
36 months of school
That's too long, way too long
Why talk about it in a song (Hey!)

Do I really have to go to 5th grade?
Nine months at school gives me bad reactions
Well still you need to learn how to calculate
Important things like compound fractions

5 times 9 is 45
45 months of school
That's too long, way too long
How many more months till we end this song? (Hey!)

6th grade I'll have gone 54 months; 6 x 9 is 54

7th grade I'll have gone 63 months because 7 x 9 is 63

8th grade I'll have gone 72 months; 8 x 9 is 72

And 9th grade I'll have gone 81 months because 9 x 9 is 81

By 10th grade I'll have gone 90 months

Cause 10x9 is 90

You're not quite done; by 11th grade you'll have gone 99 months

When you finish 12th grade, if you graduate,
You'll have been there 108

Nine months!
Nine months!
Nine months!