Decimals Add and Subtract
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1. This document provides a lesson on adding and subtracting decimals. It emphasizes lining up the decimals and notes that adding and subtracting decimals follows the same process as whole numbers. 2. Examples are provided that demonstrate adding decimals by lining them up under each other with the decimals in the same column before adding. Adding zeros as placeholders is explained to help line up the decimals. 3. Subtracting decimals is demonstrated with examples of lining up the numbers with the larger number on top and subtracting left to right, borrowing as needed from the left.
Decimals Add and Subtract
- 1. Medical Math Lesson Adding and Subtracting Decimals September - 2012
- 2. Essential Question: • How do I add and subtract decimals? It is very important that you: 1.Always line up decimals 2.Add and subtract like you always do 3.Bring decimal straight down in your answers
- 3. Adding Examples: 4.55 + 11.3 Put the first number on the top of the second number and line up the You can decimals. add a zero to help keep 4.55 everything lined up + 11.3 0 When adding or subtracting 1 5. 8 5 you always start from the right and work left.
- 4. 6.44 + 16 When there is not a decimal put one behind the 6+6=12 number. Write down the 2 and Add a zero carry the 1. to line up Line up everything 1 6.44 the decimal + 16. 0 0 22 . 4 4
- 5. 8.33 + 10.972 Annex (add) a 1 1 zero which acts as a decimal 8.330 place holder and Set up vertically and helps lining up line up + 10.972 the numbers. the decimals 1 9 .3 0 2 Adding a zero is also called annexing a zero. It doesn’t change the value of the number.
- 6. Subtracting Examples: 5.34 -2.08 Put the larger number on the top of the smaller number and line up the Don’t forget you may decimals. Need to borrow from the left to get the 2 job done’ /4 5.3 1 -2.0 8 14-8=6 3. 2 6 2-0=2 5-2=3
- 7. 28 – 15.911 Stack them and line up the decimal When there is points. not a decimal, as in the 28, Add zeros to put one line up behind the 7 99 everything, number. then 28.0001 subtract -15.911 1 2.08 9 Start borrowing from the left. Start with the first number smaller than the number under it.
- 8. Magic Square 0.5 7 4.625 8.75 The sum of each 6.375 0.5 7 row, column, and diagonal 5.25 4.625 4 must be the 2.25 8.75 2.875 same. Sums to 13.875
- 9. Assignment: Problems 1-16 to be completed without a calculator. Remember to show your work for any credit. Turn into your instructor. Edmodo quiz on addition and subtraction of decimal values.