Chapter 2 Decimals

Ordering Decimals Add 0’s to the end of the decimal so all decimals have the same number of decimal places Add 0’s to the end of the decimal so all decimals have the same number of decimal places –Eg. Put in ascending order 3.4, 2.23, 4.678, 0.2, TensUnitsTenthsHundredthsThousandths

Adding & Subtracting Decimals Remember the decimal point must be in a straight line Remember the decimal point must be in a straight lineExamples 1) ) 0.4 – ) 3 – 2.32 Put in extra 0’s at the end so all numbers have the same number of decimal places

Multiplying Decimals by 10, 100,… Move the decimal point the same number of times as the number of 0’s Move the decimal point the same number of times as the number of 0’sExamples 1) 0.43 × 10 2) × 100 3) 2.1 × 100 4) 3.76 × 1000 Fill any gaps in with 0’s

Multiplying Decimals Remove all decimal points Remove all decimal points Do the multiplication Do the multiplication Count the number of decimal places in the question and insert a decimal point in the answer so it matches the question Count the number of decimal places in the question and insert a decimal point in the answer so it matches the questionExamples 1) 0.3 × 0.2 2) 1.3 × 5 3) 28.6 × 13.6

Dividing Decimals by 10, 100,… Move the decimal point back the same number of times as the number of 0’s Move the decimal point back the same number of times as the number of 0’sExamples 1) 0.43 ÷ 10 2) ÷ 100 3) 2100 ÷ 100 4) ÷ ) 36.9 ÷ 10

Dividing Decimals You cannot divide by a decimal. You cannot divide by a decimal. You must move the decimal point forward in both numbers so the divisor is no longer a decimal You must move the decimal point forward in both numbers so the divisor is no longer a decimalExamples 1) 4 ÷ 0.8 2) 2 ÷ ) 0.03 ÷ 0.008

Fractions & Decimals Decimals-Fractions Decimals-Fractions –The number of decimal places indicates the number of 0’s eg 0.3, 0.56,

Recurring Decimals 1 digit recurring 1 dot above digit 1 digit recurring 1 dot above digit More than 1 digit recurring 1 dot at start of pattern and 1 dot at end More than 1 digit recurring 1 dot at start of pattern and 1 dot at end