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### Course: Arithmetic>Unit 6

Lesson 5: Subtracting within 1,000,000

# Relate place value to standard algorithm for multi-digit subtraction

Transition from a place value chart to standard algorithm when subtracting multi-digit numbers.

## Want to join the conversation?

• Can someone explain me what the easier way to do this
• you can put the number you are subtracting from at the top of the equation and the other on the bottom and subtract the numbers that way.
• Can we also subtract millions? Billions? Trillions? Quadrillions?
• Well, honestly i think you can but it will be hard to even subtract huge number.
• do you have more methods that you think you could share with us?
• You could simply countdown to subtract...
But that's a lot of unnecessary effort...
• Would it be correct to say that the number you're subtracting from should be greater than the number you're subtracting, so, all the digits should be greater?
• Yes!
• how do you use the box method?
• what do you mean about the box method?
this?:
1000
-528
------
472
• Why do you have to regroup when subtracting 1,000 and 528?
• its not regroup because then you would have got into the 10,000s
(1 vote)
• I do not understand the standard algorithm or whatever you want to call it. The part I do not understand is at...
(1 vote)
• Yes, this part is more tricky.
The thousand is broken into 10 hundreds.
One of these hundreds is broken into 10 tens, leaving 9 hundreds.
One of the tens is broken into 10 ones, leaving 9 tens (and still leaving 9 hundreds).
So the thousand is traded for 9 hundreds, 9 tens, and 10 ones. This makes all the subtractions possible.

There is an easier way to do subtraction problems when the top number ends with a group of 0’s on the right (with the last digit belonging to this group of 0’s). Borrow 1 from the column just to the left of this group, and subtract “all from 9, but last from 10” in the columns with this group of 0’s in the top number.

For the problem 1000 - 528 in the video, borrowing 1 in the thousands place gives 0 - 0 = 0 as the thousands digit in the answer. Then 5 from 9 is 4, 2 from 9 is 7, and 8 from 10 is 2. The final answer is 0472, or just 472.

Have a blessed, wonderful day!