Multiplication 1
|
The word ‘multiply’ was used in the mathematical sense from the late fourteenth century and comes from the Latin multi meaning ‘many’ and plicare meaning ‘folds’ giving multiplicare - ‘having many folds’, which means ‘many times greater in number’. The term ‘manyfold’ in English is antiquated but we still use particular instances such as ‘twofold’ or threefold’.
|
The × symbol for multiplication has been in use since 1631. It was chosen for religious reasons to represent the cross. We read the statement 3 × 4 as ‘3 multiplied by 4’.
In some countries a middle dot is used so 3 × 4 is written as 3.4. In algebra it is common to not use a symbol for multiplication at all. So, a × b is written as ab. |
Easy
One way of thinking of multiplication is as repeated addition. Multiplicative situations arise when finding a total of a number of collections or measurements of equal size. Arrays are a good way to illustrate this. Some division problems arise when we try to break up a quantity into groups of equal size and when we try to undo multiplications.
Addition is a useful strategy for calculating ‘how many’ when two or more collections of objects are combined. When there are many collections of the same size, addition is not the most efficient means of calculating the total number of objects. For example, it is much quicker to calculate 6 × 27 by multiplication than by repeated addition.
ModerateTask:
|
Task:
|
Use a pack of playing cards. Form a small group. One student deals 3 cards to each player.
The player with the highest score wins the round and scores a point.
If some of the players find it to difficult use paper and pencil or a calculator.
The player with the highest score wins the round and scores a point.
If some of the players find it to difficult use paper and pencil or a calculator.
Difficult
Task:
Make a paper ruler – place ruler on the screen to measure how many centimeters from one location to another. Then convert the distance from the scale to get actual distance.
How far between: Darwin and Tennant Creek: Darwin and Mount Isa: Darwin and Townsville: Darwin and Rockhampton: Darwin and Bundaberg: Bundaberg and Alice Springs: Bundaberg and Mount Isa: Bundaberg and Tennant Creek: Bundaberg and Rockhampton: To convert into kilometers you need to take the amount of centimeters and multiply by 200. E.g. - 200 X 6 ----- 1200km’s Plan some other journeys. |