65.1 50.34 DECIMALS 1,234,567 18.0076

Adding, subtracting, Multiplying & Dividing Decimals. Example Subtract 3.0025 from 12.1 Solution 12.1000 N.B. For adding and subtracting decimals keep the decimal points lined up - 3.0025 9.0975

Example Multiply 576 by 23 Solution 576 x 23 1728 11520 13248

12.36 Example Multiply 12.36 from 4 Solution ( 2 d.p.) x 4 ( 0 d.p.) 49.44 ( 2 d.p.) NB When multiplying decimal numbers. Ignore the decimal point until the very end i.e. 12.36 has 2 d.p. 4 has 0 d.p. Therefore Answer will have (2 + 0) = 2 dec places

2.31 Example Multiply 2.31 by 0.7 Solution ( 2 d.p.) Total 3 d.p. x 1.617 ( 3 d.p.)

25.6 120.32 Example Multiply 25.6 by 4.7 Solution ( 1 d.p.) 2 d.p. x 1792 1024 120.32 ( 2 d.p.)

3. 3 8 1 5 Example (dividing by a whole no.) Divide 27.052 by 8 Solution 3. 3 8 1 5 8 27.0520

Example (dividing by a decimal) Divide 34.86 by 0.7 Solution Write 34.86 ÷ 0.7 as a fraction: NB The method here is to make the 0.7 into a whole number – remembering that what we do to the bottom no. we must do to the top so they are equivalent. x10 34.86 0.7 348.6 7 x10 Now we have a whole no.

Divide 34.86 by 0.7 Solution contd. 4 9. 8 8 348.6 ANS: 49.8

90 ANS: 90 Example (dividing by a decimal) Divide 3.6 by 0.04 Solution 360 4 x100 Now we have a whole no. 90 ANS: 90 4 360

Working with powers of 10 Examples Eg (exempli gratia) 2.56 x 10 = 25.6 2.56 x 1000 = 2560 31.8 ÷ 10 = 3.18 5.56 ÷ 1000 = 0.00556

Further Examples Eg (exempli gratia) 2.89 x 20 = 28.9 = 57.8 0.4261 x 300 = 42.61 x 3 = 127.83 45 ÷ 40 = 4.5 ÷ 4 = 1.125 31.92 ÷ 3000 = 0.03192 ÷ 3 = 0.01064