NUMBERS • NUMBER SYMBOLS 11
Reading long numbers and dates
To turn a long Roman number or date into a Hindu-Arabic
number, we break it into smaller parts then add up the parts.
MCMXCVIII
IV V VI VII VIII IX
Answers on page 319
TRY IT OUT
The Babylonian number system is
more than 5000 years old
REAL WORLD MATHS
4 5 6 7 8 9
Now have a try at writing these
years as Roman numerals:
1666 2015
“C” before “M” means
“100 less than 1000”
Let’s work out the
number CMLXXXII.
First, we break it into
four sections.
Next, we work out
the values of the
different sections. When
we add the values
together, we get the
answer: 982.
= 900 +
= 50
= 30
= 2
982
1000 − 100
L
3 × 10
2 × 1
What’s this year?
Zeros help us
read the time
correctly on a
24-hour clock
=
=
=
Zero the hero
Not all number systems have a symbol for zero
(0) as we do. On its own, zero stands for “nothing”,
but when it’s part of a bigger number, it’s called the
place holder. This means it “holds the place” when
there is no other digit in that position of a number.
The Romans used letters as
symbols for numbers
CM L XXX II
CM
XXX
II
Name the date
Today, we sometimes see dates written
in Roman numerals. Can you use what
you’ve learned to work out these years?
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