Page： 161

Before the invention of writing how did people keep records?

They made pictures on soft earth or sand.

But rain and wind and waves quickly washed away such records.

Smooth stone or wood was better, and best of all, the smooth stone walls of caves whose roofs kept the rain and wind away.

It may be that drawings copied on page 142,or others like them,were records made by early humans.

Someone recording animals on a cave wall may have taken pleasure in the drawing for itself and become the first artist.

Page： 162

How did a man know how many sheep he owned?

Sometimes he used small stones or sticks, putting one of them into a bag or pocket for each sheep he had.

When he came to the end of his sheep, the number of stones in the bag was the same as the number of his sheep.

The stones and sheep were equal in number.

The stones gave him the record of how many sheep he owned.

When a sheep died he could take a stone out of the bag.

And when lambs were born he could put in another stone for each lamb.

Page： 163

Sometimes a record was made by taking a sharp,hard stone and making cuts on a stick.

The number of cuts on the stick equaled the number of things to be record.

Then the stick was cut in half down the middle so that each half had half of every cut on it.

The two half sticks were tallies.

If they were put side by side, the halves of the cuts came together.

They tallied.

One man took one tally and another the other, and both them had the record.

Page： 164

Tallies are some of the earliest and simplest records of the numbers of things.

They tell how many things have been counted.

Even today in the bank,a person who takes money in and gives it out is sometimes named a teller.

The shelf or table where the teller works is a counter.

On it the teller does the counting of the money coming and going out, and keeps a record of all this in an account book.

A person who makes a statement tells something.

Most banks make a statement every month to each person banking with them to tell them what their account is.

The statements tell them how much money they have in the bank at that date.

Then both they and the back have the record straight.

To get these statement ready, the banker has to take the amount of money given out from the amount of money put in.

Page： 165

Bank tellers must keep a complete record of the money they take in and give out.

This is their way of making certain that their accounts are in order.

Banking is a very important sort of business.

A bank must keep all its accounts in good order and the statements which the bank makes must be true statements.

Page： 166

How do we know whether someone is telling the truth?

If a man tells another that he will give him three bags of grain for one sheep, the other will know whether he told the truth when he gets the grain or doesn't.

The man may,or may not, have meant to give the grain when he said he would.

He may not have meant to say anything but the truth.

But if he did not give the grain later, he was not true to his word.

We sometimes know whether a man is telling the truth by the look in his eye, or the sound of his voice.

Page： 167

In early times, before people invented money, they did all their business by exchange of goods.

People traded with others by exchanging goods they were willing to give up for goods they wanted more.

Exchange of things still goes on in some parts of the world today.

After the invention of money,trade increased.

It is our experience that money can be a great help in making trade easier and in keeping business in better order.

If you want something and have the money for it,you can buy it.

You do not have to keep asking yourself whether you have something which the other person will be willing to take in exchange for what you want.

Page： 168

Early people did things with their hands which we do with instruments or by machine.

Fingers were made before forks.

Among their early uses, fingers made good counters.

We still use the number ten as the key to our number system because we have ten fingers.

Many people today still count on their fingers, and others use an abacus.

An abacus in a frame with little balls threaded on wires.

The balls are pushed from side to side on the wires.

The invention of the abacus made it possible for the balls on one wire to represent the numbers up to ten, on the next wire tens up to a hundred, the next, hundreds, and so on.

Page： 169

The most important number in the number system used commonly today is zero.

Zero is so easy to use that it is hard to understand why it was invented long ago.

It is thought to be not much more than a thousand years old and no one knows who invented it.

We use zeroes to change numbers to others.

Zero to the right of a number makes it ten times its size.

Two zeroes make it a hundred times its size.

Six zeroes after one make it mean one million.

Schools today teach a child to add, subtract, multiply and divide numbers.

Here are examples.

Page： 170

People made their way about on the earth,over mountains, down rivers and across seas long before they had a number system or could make or use a compass.

Nobody knows who invented compass.

The Chinese, Arabs,Greeks and Italians, among others,say they did.

When people became able to work out the relations of lines and spaces to one another, and could measure distances and angles, the science of geometry,earth measuring, began.

People went on then from measuring fields and bits of land, to measure the size of the earth itself.