Temperature, time, receipts and bills They're even in the pound! Decimals are my thing You see them all around Temperature, time, receipts and bills They're even in the pound! Can you think of any more examples? April 2008. Kindly contributed to the Adult Basic Skills Resource Centre http://www.skillsworkshop.org by Taz Kausar-Javaid, The Oldham College Kausar-Javaid, Tasneem Tasneem.Kausar-Javaid@oldham.ac.uk Teaching notes: on slide 2 - I usually ask the students to think of examples of where they see the decimal in practice – i.e. petrol prices, fat content on food labels, etc. This can be done as a paired activity - the groups then feedback their ideas and these are inputted on slide 2 whether it is done as a PowerPoint or OHT presentation. Taz Main curriculum links N2/L1.5 Add, subtract, multiply and divide decimals up to two places. N2/L1.6 Multiply and divide decimals by 10 and 100.

DECIMALS DECIMALS

PLACE VALUE 1 4 3 7 5 9 Hundreds 100s Tens 10s Units 1s . Tenths 10ths Hundredths 100ths Thousandths 1000ths 1 4 3 7 5 9

MULTIPLYING BY 10, 100 ,1000 x 10 x100 x 1000 22.0 220 2200 22000 16.5 165 1650 16500

DIVIDING BY 10, 100 ,1000 ÷ 10 ÷ 100 ÷ 1000 19500 1950 195 19.5 234 23.4 2.34 0.234

ADDITION AND SUBTRACTION LINE UP DECIMAL POINTS EXACTLY ADD OR SUBTRACT THE SUM E.g. 2.34 + 18.034 and 234 – 3.56 18.034 234 +2.34 - 3.56

MULTIPLICATION 3.45 x 2.1 Ignore the decimal points Multiply as normal Put the decimal point back into the answer 345 x21 Put the decimal point back into the answer. Look at the question, there are 3 numbers after the decimal place so work the decimal place back into the answer.

Division To divide a whole number into a decimal Divide as normal Keep the decimal points in line Round the answer to sensible number of figures where necessary E.g. 172.6 ÷ 4 4 Add 0s to the end if need be Note – check by multiplication

Divide a decimal by a decimal Change the number you are dividing by into a whole number. Do this by multiplying by 10, 100, 1000 Do exactly the same to the number you are dividing Divide to find the answer

continued E.g. 7.4 ÷ 0.05 Multiply the 0.05 by 100 to make it into a whole Number. Then do the same to 7.4. 5 Check by multiplication – 148 x 0.05 = 7.4

continued Find 31.52 ÷2.4 Multiply 2.4 x 10 = 24 2 4 3 1 5 . 2 = 13.133333333333333333333333 So we round to 13.13 (to 2 dp)