Decimals are my thing You see them all

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? 1

DECIMALS 2

PLACE VALUE Hundreds 100 s Tens 10 s Units 1 s . Tenths 10 ths Hundredths 100 ths 1 4 . 1 3 7 . 5 0 Thousandths 1000 ths 9 3

MULTIPLYING BY 10, 1000 0 x 1000 22000 16. 5 16500 4

DIVIDING BY 10, 1000 ÷ 1000 1950 195 19. 5 234 23. 4 2. 34 0. 234 5

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 +2. 34 234 - 3. 56 6

MULTIPLICATION • 3. 45 x 2. 1 • Ignore the decimal points • Multiply as normal • Put the decimal point back into the answer 345 x 21 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. 7

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 Keep the decimal points in line 4 Add 0 s to the end if need be Note – check by multiplication 8

Divide a decimal by a decimal • Change the number you are dividing by into a whole number. • Do this by multiplying by 10, 1000 • Do exactly the same to the number you are dividing • Divide to find the answer 9

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 10

continued • Find 31. 52 ÷ 2. 4 Multiply 2. 4 x 10 = 24 Multiply 31. 52 x 10 = 315. 2 24 315. 2 = 13. 1333333333333 So we round to 13. 13 (to 2 dp) 11