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## Early math review

### Course: Early math review>Unit 6

Lesson 3: Subtracting 1s, 10s, and 100s

# Subtracting 1s, 10s, and 100s

Sal subtracts 3-digit numbers by subtracting ones, tens, and hundreds.

## Want to join the conversation?

• at is the word hundred a number and place value?
• One hundred is a number, but hundred is a place value.
• What is 1000-900? I know its pretty easy i just wanna see you do it.
• This problem is as easy as doing 10 - 9. We can just not pay attention to the last two zeroes for now, and get 10 - 9.
10 - 9 = 1
Now that we have a sum for that, we can just add the zeroes back on again, because 0 + 0 = 0, so it wouldn't change anything but the place value.
This means that our final answer is 100.
(Sorry for giving you the same explanation twice, but you did ask the same question twice)
• what is e x 4 =
• It depends on what “e” means in the equation. “e” can represent the number 2.7182818284590452353602874713527... (You’ll learn this is higher level math courses) or it could be a number of your choice if it is a variable. Hope this helps!
• what is 10000000000-1=?
• 9,999,999,999. AKA: 9 billion, 999 million, 999 thousand, 999 :)
• If 300-200=100, what is 200-300?
• If you have for example, 400 - 150 = 250, then if you switch it around, so that it is 150 - 400, it will always be -250.

So 300 - 200 = 100, switch it around (200 - 300) and we get -100 instead of 100.

Im sorry if this is confusing but it's a neat trick that can really come in handy.
• Should I use I calculator if I think I can do it in my head?
(1 vote)
• It's useful to be able to perform arithmetic (addition, subtraction, etc.) in your head, and you'll get faster at it than using a calculator! If you're unsure of the value you come up with, you can always use a calculator to check your result.
• if 500+500=1000 what is 50+50=?
(1 vote)
• That would be 100! I hope you are having a great day!
• How to Add without Regrouping
Place the addends one on top of the other so that the place values fall in the same columns.
Add each column together separately, starting with the 1s place.
The sums go below each column, underneath the line.
Jul 1, 2019