Grade 2 Number and Operations in Base Ten

Grade 2: Number and Operations in Base Ten Use place value understanding and properties of operations to add and subtract 7. Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

82 -58 If you look at ones place, you have eight ones and two ones. However, you can not take eight ones away from two ones.

82 -58 The first thing we need to do is regroup. We need to regroup in the tens place because that is where we need to ‘borrow’ ones from.

7 12 82 -58 We need to take one of the tens from the 80 and make it ten ones. Now we have 12 ones that we can subtract 8 from.

4 12 82 -58 4 12 minus 8 leaves us with 4 ones.

4 12 82 -58 24 Then we move to the tens and subtract 7 minus 5 which leaves us with 2 tens.

4 12 82 -58 24 So, the answer to the problem 82 -58=24.

Please contact me if you have any questions at ltrimble@ashland. edu. You can also find additional resources at the following websites: http: //www. mathplayground. com/howto_regroup. I. html http: //www. mathsisfun. com/numbers/subtractionregrouping. html http: //www. myschoolhouse. com/courses/O/1/40. asp