If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Class 4>Unit 1

Lesson 2: 3-digit subtraction

# Methods for subtracting 3-digit numbers

Subtract 357-156 using place value strategies.

## Want to join the conversation?

• I do not really understand because write now I am doing 251-92 is the same as blank - 100 and I do not get the answer
• In a subtraction problem, if we add the same thing to both numbers, the answer (difference) does not change.

Note that 8 needs to added to 92, to get 100. Adding 8 to 251 gives 259.

So 251-92 = 259-100, so the number in the blank is 259.

This is one of the tricks for changing a harder subtraction problem to an easier one, without changing the answer (difference). From this trick, it is easy to see that 251-92 = 159, because 251-92 = 259-100, which is 159.

Have a blessed, wonderful day!
• I feel there is only one simple way on doing this:
4 16 <----- regrouping
456
-347
------------
1 0 9

I feel it is the simplest way to do subtracting. His way to me does not make sense? Is that an okay thing for me to feel?
• There is nothing wrong with doing your work differently as long as you understand whats going on!
• What doese evaluate mean
(1 vote)
• In math, to evaluate an expression means to calculate its numerical value.

In English, to evaluate something is to judge how good or bad it is, by considering its strengths and weaknesses.
• Is this solvable 1,000
+ 432
________?
(1 vote)
• what 9.16 time 9.16
• well if you multiply 9.16 by 9 and add it to 9.16x.16 you would get the awnser
• hi what is the best way to subtract?
• subtract individually(by themselves) starting at the back if the number below is too big then take from the next place value
• what is 100 -55
• my only week point in math is rounding