1. MathematicsPrathomsuksa 5

2. Vocabulary structure text 3. additionthe process of calculating the total of a group of numbers 4. subtractionthe process of taking one number or amount away from another number or amount 5. differencethe result of subtracting one number from another 6. sumthe total amount that you get when you add two or more numbers together. 7. carryto put a number into another column when doing addition. 8. Listen and Answer Activity 9. Answer 10. Times up 11. Addition Properties and Subtraction Rules What they are and how they help 12. Addition Properties Commutative Property - Changing the order of addends does not change the sum. Example 3 + 4 = 7; 4 + 3 = 7 Identity Property - The sum of zero and any number is that number. Example: 9 + 0 = 9; 0 + 5 = 5 Associative Property - Changing the grouping of addends does not change the sum. Example: (3 + 2) + 5 = 12; 3 + (2 + 5) = 12 13. Benefits of knowing the Addition Properties Better fact mastery Memorization needs reduced. Increased number sense. Use order changes for easier groupings (complement numbers = sums of 10 or 100) Short cuts in adding more than 2 numbers Group to allow more mental addition Better groundwork for algebraic concepts Solving for missing numbers or variables 14. Adding Two Digit Numbers with Regrouping (Carrying) You add numbers by adding the digits in each place value column from right to left. Add each column starting with the ones place. If the number is more than ten you regroup or carry. Example: Add 78 + 68 =? 15. Step-1: Line up the number by place value. 16. Step-2: Add the ones place. (7+8=16) 16 islarger than ten so you have to regroup or carry. Place the 6 under the ones place column and place the 1 above the 7. 17. step-3: Add the tens place column including the 1 you place above the7.(1+7+6=14) then place the 14 next to the 6 in the answer row. 18. Subtraction Rules Subtraction is the inverse of addition (it undoes addition) The subtrahend is subtracted from the minuend to find the difference. When the minuend is equal to the subtrahend the difference is always zero. When zero is the subtrahend the difference is always equal to the minuend.14 Minuend -8 Subtrahend6 Difference 19. How Subtraction Rules Help Use addition to check subtraction of larger numbers. Faster recall of subtraction facts. Better responses in choosing the correct operation in word problems. 20. Subtracting Two Digit Numbers with Regrouping (also called Borrowing or Renaming) Subtract numbers from right to left. If the digit is not large enough to subtract from, regroup or borrow one from the next place to the left. 21. Example: 36-27=?36- 27 22. 6 is less than 7, so borrow one from the 3. The 6 become 16 and the 3 becomes 2. Now subtract 7 from 16 = 9 Subtract 2 from 2=02 1 36- 27 09 23. TheHow to use .. We use the when it is clear which thing or person we mean Example: -Who is the best player in your team? (= there is only one best player) - My office is on the first floor. (= the first floor of the building) 24. the same Example: We live in the same street. (not in same street) sun/ moon/ world/ sky/ sea/ country Example: The sky is blue and the sun is shining. Do you live in a town or in the country? police/ fire brigade/ army Example: My brother is a soldier. Hes in the army. What do you think of the police? 25. top/ end/ middle/ left Example: My house is at the end of the street. The table is in the middle of the room.musical instruments Example: Paula is learning to play the piano. We do not use the with: television/ TV Example: I watch TV a lot. Whats on television tonight? But Can you turn off the television? (= the TV set) 26. Breakfast/ lunch/ dinner Example: what did you have for breakfast? (not the breakfast) Dinner is ready! next/ last + week/month/year/summer/Monday etc. Example: Im not working next week. (not the next week) Did you have a holiday last summer? (not the last summer)