Thursday, September 30, 2010

Grades and Addition

Please take a close look at the grading sheet that came home with you from open house or today from school with your child. This will help you to understand how the 1, 2, 3 grades from second grade transfer to A, B, C, D, and F's in third grade. We realize that this is a huge transition for both you and your child. Please stay patient with both them and me. If your child is struggling with a concept at night on homework and is screaming, crying, and you are ready to tear your hair out or want to kill me for assigning such a horrific thing, please write a note and let me know that you couldn't go any further and your child needs help. Do not let you or your child get to such a huge frustration level. My goal is to have them get frustrated with me at school and come home to practice and show you their success at home.

Estimating Differences
(Rounding) (Subtract)
When you estimate a difference, you will round the numbers either to the nearest 10s or 100s place. Then subtract the two rounded numbers to get an answer that is an estimate of the difference.

Adding Two-Digit Numbers

Rule 1: Line up the numbers by place value.
Rule 2: ALWAYS start in the ones place.
Rule 3: Work from top to bottom.

Example 1: 25+32= Have your child line up the place values and then add 5+2 and then 2+3.

Example 2: 37+45= When you have to re-group ("carry" to us who went to school more than 10 years ago), I still have my kids start in the ones place and add up 7+5=, but when they get that answer I have them arrow over to the right and write down the answer to the ones place to make it easier for them to put the ones with the ones and the tens with the tens. Then add the tens place, starting from the top with the re-grouped one and working our way down to 3 and then 4.

Adding Three Digit Numbers

** The rules remain the same.**

Example 1: 342+232= Add 2+2, then 4+3, then 3+2.

Example 2: 546+245= Add 6+5, arrow over to the right and write down the 11, put the one in the ones place and the other one above the tens place, add the 1+4+4, then add the hundreds 5+2.

Example 3: 268+379= When you need to re-group twice, have them arrow over to the right for the ones place and over to the left for the tens place. Add 8+9, arrow the 17 to the right of the ones, put the 7 under the ones place and re-group the 1 over the tens place, add from top to bottom in the tens place 1+6+7=14, arrow the 14 to the right of the plus sign, place the four under the tens and the one on top of the hundreds, finally add the hundreds from top to bottom 1+2+3=6.

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