Mathematics Place Value - Decimals

The aim of this powerpoint is to teach you about place values within decimal numbers as well as how to read and write decimal numbers. EITHER Take notes as you go along (and include some examples) OR If you have not already done so (after the previous powerpoint on integers), at the end of the powerpoint, printout the notes called Calc1a

Place Value Column Labels You have already met the place value columns for integers: … Millions Thousands HTU … Million 1 000 000 Hundred Thousand 100 000 Ten Thousand 10 000 Thousand 1000 Hundred 100 Ten 10 Unit 1 The integer (ie. whole number) parts of any number lie to the left hand side of the decimal point. If the decimal point is not shown then you can write it in directly after the units (click to see it appear).

Decimals After the decimal point we get the ‘decimal column’ values These are worth less than 1. As before moving right to left, 10 of 1 column is worth 1 of the next column. Although columns go on forever, we will focus on the tenths, hundredths and thousandths columns Tenth 1/10 0.1 Hundredth 1/100 0.01 Thousandth 1/1000 0.001 Hundred 100 Ten 10 Unit 1

Writing decimal numbers in words Write out the whole number part as you have previously been taught, then write ‘point’ followed by each individual digit (without the column value). E.g. 27.304 in words would be… … TTh Th H T U . Tth Hth Thth 2 7 . 3 0 4 Twenty-seven point three zero four

Practice Have a go at writing these numbers in words on paper. When you have ALL your answers, click to check them. 1) 5.8 2) 29.15 3) 4008.067 … HTh TTh Th H T U . Tth Hth Thth 2 9 . 1 5 Twenty-nine point one five 5 . 8 Five point eight 4 0 0 8 . 0 6 7 Four thousand and eight point zero six seven

Writing decimal numbers in figures Follow the method for whole numbers and then write the decimal digits down as per instructions (i.e. the point and then the single digits in the order given). E.g. Seven hundred and one point zero six three … TTh Th H T U . Tth Hth Thth 7 0 1 . 0 6 3

Writing decimal numbers in figures Watch out, sometimes, the column value of the decimal digit may be stated – put that digit in the right column and any zeros needed to fill gaps in the spaces before it! E.g. Nine and three hundredths … TTh Th H T U . Tth Hth Thth 9 . 3

Practice Have a go at writing these numbers in figures on paper. When you have ALL your answers, click to check them. 1) Fifty-eight point six three 2) Four hundred and twelve and six tenths 3) Eighty-seven and fourteen thousandths … HTh TTh Th H T U . Tth Hth Thth 5 8 . 6 3 4 1 2 . 6 8 7 . 1 4 Did you remember that ‘ten’ in the thousandths column = 1 in the hundredths column?

What next? (Page 1 of 2) If you haven’t made any notes or copied any examples, questions and answers out during this presentation, print out the notes called Calc1a. Read through them and make sure you answer any questions. Work through the MyMaths lesson (and then the online homework) called Decimal Place Value found at: http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=decimals/decimalPlaceValue&taskID=1076 http://www.mymaths.co.uk/tasks/library/loadTask.asp?title=decimals/decimalPlaceValueOH&taskID=1076 Save and complete the worksheet called PVDec-S1.xlsx If you want some more help or practice with decimal place value work through the MyMaths lessons and online homeworks listed on the next slide…

What next? (Page 2 of 2) Work through the MyMaths lesson (and then the online homework) called Introducing Decimals found at: http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=decimals/decimalIntro&taskID=1378 http://www.mymaths.co.uk/tasks/library/loadTask.asp?title=decimals/decimalIntroOH&taskID=1378 Work through the MyMaths lesson (and then the online homework) called Decimal Number Lines Intro found at: http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=decimals/decimalLinesEasy&taskID=1379 http://www.mymaths.co.uk/tasks/library/loadTask.asp?title=decimals/decimalLinesEasyOH&taskID=1379 Work through the MyMaths lesson (and then the online homework) called Number Lines found at: http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=decimals/decimalLines&taskID=1009 http://www.mymaths.co.uk/tasks/library/loadTask.asp?title=decimals/decimalLinesOH&taskID=1009 Now move on to the Calc1b-Order powerpoint