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Lesson 6: Strategies for subtracting two and three-digit numbers

# 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!
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• How don't you know how to subtract
• 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.