Review All Operations with Decimals Adding Subtracting Decimals

Review: All Operations with Decimals

Adding & Subtracting Decimals *Remember to line up the decimals when adding & subtracting numbers with decimals. Example 1: Example 2: 13. 45 + 9. 2 17. 53 – 8. 6 13. 45 + 9. 2. 22. 65 17. 53 - 8. 6. 8. 93

Multiplying Decimals *When multiplying decimals, multiply normally. Count how many digits are on the right side of the decimal point. Then place the decimal point in your answer so the same amount of digits to the right of the decimal point. Example 3: 14. 65(7. 2) 14. 65 x 7. 2 2930 + 102550 105. 480 . There are two digits to the right of the decimal in 14. 65 and one decimal to the right in 7. 2. This means that our answer has to have a total of three digits to the right of the decimal. The decimal point should go in between the 5 and 4.

Dividing Decimals When dividing decimals, if the divisor is not a whole number, move the decimal point to make it a whole number. Then move the decimal point in the dividend the same number of places. Then bring up the decimal point directly above the decimal point in the answer. Example 4: 138. 84 ÷ 8. 9 *Change the divisor 8. 9 to 89. This means you have to move the decimal one space to the right and in the dividend and make 138. 84 change to 1388. 4. 15. 6 -89 498 -445 534 -534 0

PEMDAS with Decimals *Be sure to follow the order of operations (PEMDAS) when you have multiple operations in a problem. You also have to remember how to add, subtract, multiply & divide decimals. Example 6: 18. 2 ÷ 2 – 6. 39 9. 1 – 6. 39 2. 71 PEMDAS Divide Subtract Example 5: PEMDAS (4. 2 + 8. 4) ÷ 2 + 13. 458 Parenthesis 12. 6 ÷ 2 + 13. 458 Divide 6. 3 + 13. 458 Add 19. 758

Practice Problems Show all of your work and do not use a calculator. 1. 24. 682 + 12. 6 = 37. 282 3. 21. 34 (4. 6) = 98. 164 5. 2. 3(6. 3 -4. 12) = 5. 014 2. 34. 754 – 9. 76 = 24. 994 4. 80. 192 ÷ 6. 4 = 12. 53 6. 7. 5 + 6. 9 ÷ 3(2) = 12. 1