Key: 1. A 2. language 3. people 4. C 5. B 6. C
（三）
A Leg Walking Right
Here are some signs + - x…, the signs are very different. They mean very different things. When you see them, you know what to do. This sign + means that you will add some numerals. This sign—means that you will take one numeral away from another. You will subtract（减去）. What will you do when you see x and… ?
Our signs are easy to read. They are easy signs to remember. Look at these two signs… .The ancient Egyptians used these signs. A picture of a leg walking to the left told them to add some numerals. A picture of a leg walking to the right told them to subtract.
In the 1500s people used this printed（印刷的） sign & to add numerals. After a while the sign began to look like this… .Later, the sign became +.
How much is 2…2?
