Adding or subtracting 10 or 100 mentally

Mentally add or subtract ten or one hundred within one thousand

Problem types

Hundreds, tens, and ones
Ten more and ten less · Earlier idea
Changing the tens digit by one extends to changing the hundreds digit by one.

Explaining why a strategy works
Adding and subtracting within 1,000 · See it applied
Adding or subtracting tens and hundreds mentally is the first step in adding and subtracting three-digit numbers.
Converting to a smaller unit · See it applied
Converting between metric units multiplies or divides by 10, 100 or 1000, which is mental tens and hundreds.
Powers of 10 and place value · Extend the idea
Shifting a value by ten or one hundred in place value becomes multiplying and dividing by powers of ten.
The standard multiplication algorithm · See it applied
Multiplying by 10 or 100 mentally shifts digits and is the first partial product in a multi-digit multiplication.

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