![Picture](/uploads/9/4/0/9/94096675/add.png?250)
You need to develop an understanding of properties related to addition and subtraction:
• Identity property: Adding 0 to or subtracting 0 from any number does not affect the value of the number (e.g., 6+0=6; 11– 0=11).
• Commutative property: Numbers can be added in any order, without affecting the sum (e.g., 2+4=4+2).
• Associative property: The numbers being added can be regrouped in any way without changing the sum (e.g., 7+6+4=6+4+7).
Easy
Toss 3 dice together and find the total. What order did you add the numbers in?
Discuss your strategies with a friend. Task:
Magic Squares are square grids with a special arrangement of numbers in them. These numbers are special because every row, column and diagonal adds up to the same number. 15 is the magic number. Work this out just from knowing that the square uses the numbers from 1 to 9.
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Moderate
Task:
Decimals are used widely. Our money is based on a decimal system. Common measurements such as the height of students in a class, the price of petrol or the amount of gas used for heating your home are usually expressed using decimals.
The word decimal comes from the Latin word decem, meaning ‘ten’. Decimal notation uses tenths, hundredths, thousandths, and so on, as well as units, tens, hundreds, thousands, and so on. The decimal point in each number should be lined up one under the other. |
The vertical addition algorithm is shorthand for adding hundreds to hundreds, tens to tens, ones to ones, tenths to tenths, and so on. It is important to line up the place value columns when lining up the decimal point.
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