COMPUTATION WITH POSITIVE INTEGERSYear 7

ROMAN NUMERALS

The Roman Numerals are below.

Number 1 5 10 50 100 500 1000

Roman Numeral

I V X L C D M

A special subtraction method involved using a specific order for numbers such as 4, 9, 40, 90 and so on. This was done to save space. For example, instead of writing 90 as XXXXXXXXX or LXXXX, the Romans wrote it as XC (100 – 10 = 90, i.e. 10 subtracted from 100)

HERE ARE SOME EXAMPLES OF ROMAN NUMERALS

EXAMPLES OF ROMAN NUMERALS

1. Write each of the numbers in Roman Numerals.

a) 3

b) 15

c) 144

2. Write each of the numbers in Hindu Arabic.

a) CCCXLVI

b) DCXIII

c) XCIV

QUESTIONS

1. Write the following number in Roman Numerals

a) 4

b) 11

c) 99

d) 2014

e) Your Birth Year

2. Write the following in Hindu Arabic

a) XVI

b) XL

c) LXII

d) CXV

e) XXIX

TO DO: Grab a piece of blank paper from the teachers

desks. Draw you birth month calendar but instead of using

hindu-arabic numbers use roman numerals. Here is this years calendar. Make sure it is neat and use a ruler.

PLACE VALUE

The numerals we use today are called Hindu-Arabic numerals. It uses only ten symbols (called digits).

We can write any whole number, providing we understand the place value of each digit.

So 4 can mean 4 or 40 or 4000, depending on its position in the numeral.

EXPANDED NOTATION

3 x 1000 + 2 x 100 + 5 x 10 + 4 x 1 (or 3 x 103 + 2 x 102 + 5 x 101 + 4 x 1) is said to be the expanded form of the basic numeral 3254.

EXAMPLE

1. Write down the value of the digit 4 in these

numbers.

a) 437

b) 543 910

c) 4589

2. Write 517 in expanded form.

3. Write in basic form

TO DO

Ex 1B pg 12 Q1 – 12

TO DO

Ex 1C pg 15 Q1 – 11, 13, 14, 18, 19 Ex 1D pg 20 Q4 – 8 Ex 1E pg 25 Q4 – 8 Ex 1F pg 28 Q4 – 8 Ex 1G pg 33 Q3 – 9

ESTIMATING AND ROUNDING POSITIVE INTEGERS

Estimates or approximations to the answers of problems can be found by rounding numbers to the nearest 10, 100, 1000 etc.

If the next digit is 0, 1, 2, 3 or 4 then round down.

If the next digit is 5, 6, 7, 8 or 9, then round up.

EXAMPLES

Round these numbers as indicated.

a) 86 (to the nearest 10)

b) 4142 (to the nearest 100)

c) 65 (to the nearest 10)

d) 1232 (to the nearest 1000)

TO DO

Ex 1H pg 37 Q2 – 7, 9 - 11

ORDER OF OPERATIONS

BracketsIndicesDivision OR MultiplicationAdditionSubtraction

Brackets Other

Division

MultiplicationAdditionSubtraction

EXAMPLES

1. Use order of operations to evaluate these expressions.

a) 6 + 10 ÷ 2

TO DO

Ex 1I pg 41 Q2 – 6, 8 – 9, 11, 12