Abacus (ab-uh-kuhss) - noun
This is a tool normally made with a wooden
frame and wooden (or sometimes metal) rods
inside it. These rods are in rows. On these rods
are beads with the rods running through the
middle of the beads so the beads are easy to
move up and down the rods.
In ancient times because there was no pen and
paper, and most people could not read or write,
to help them with counting, numbers were shown
on the abacus with beads. A bead in the first row
is equal to one, a bead in the second row equals ten, in the third row equals a
hundred and so on.
The purpose of the abacus is to add, subtract, divide or multiply numbers.
The abacus was originally developed about 5000 years ago in China to help
salespeople count money and goods. It then became used in other countries.
In most countries it has now been replaced by calculators, while it is still used
in some places in Asia and Africa. It is also used in some pre-schools to teach
children about numbers.
Origin: Although the Chinese originally developed the abacus, the origin of
the English word comes from a Greek word, abax, which meant a „counting
board‟. It also comes from the idea that people used to spread sand over a
surface and then draw on it or placed beads or stones on the sand to help with
counting.
Bisect [bai-sekt‟] - verb
To bisect means to divide into two equal
sections. Lines, angles and other things
can be bisected. The thing that does the
bisecting is called the “bisector”.
You can cut things in messy ways or in
parts that are equal. The word “bisect”
was created for the idea of an exact
cutting in 2 equal parts.
In life you bisect things very often. If you
have to share a cake between you and
your brother, you would want to make sure it is cut exactly in half, and his
piece is not bigger than yours. For that, you need to bisect the cake.
Also say, if you are an engineer and you are designing an airplane you would
draw the full wing span (how long it is from the end of one wing to the end of
the other) then you would bisect your drawing and that would give you the
exact middle so that when you finished your drawing of your airplane it is
totally balanced without one wing being shorter than another.
Did you know that in Maths, when you have an equilateral triangle (all sides
equal) and we bisect angle „A‟ we find that the line bisecting it bisects side BC
in half.
A
B
C
Origin: The word bisect comes from Latin word „bi‟ which means “two” and
Latin word „secare‟ which means “to cut”. So they join up and mean “to cut in
two”.
Calculation [kal-kyoo-la‟ shun] – noun
A calculation is the noun for “calculate”
(See calculate in this dictionary).
When you do a calculation, you are working
out an answer or an amount of something
by using Arithmetic (in other words by
adding, multiplying, subtracting or dividing
numbers). For example, when you did a
calculation you found out that 2 + 3 = 5.
The word calculation also means an estimate. When you are working out an
estimate amount, you are working out more or less what you think the result
will be, such as doing a calculation of what something might cost, weigh or
measure.
Example: His calculation of how much money they needed for the trip was
correct because they had enough money to pay for everything they needed on
their trip.
The opposite of calculation is “miscalculation”. That‟s when your calculation or
estimate is wrong.
Example: The jacket was very big for him because of the miscalculation of the
dressmaker’s measurements.
Origin: The word „calculation‟ comes from the Latin word “calculare” meaning
“to count using small stones”. Now, the Latin word „calculare‟ comes from old
Latin word “calculus” which means “stone”. When people first started counting
they used little stones.