Place Value
• the value of a digit depending on its place in a number.
• in the decimal system, each place is 10x bigger than the place to its right.
• the decimal system uses 10 digits to show all numbers 0,1,2,3,4,5,6,7,8,9
by using place value and a decimal point to separate
whole numbers from decimal fractions.
• standard form is the usual way of writing numbers in decimal notation, i.e.
standard form = 876, expanded form = 800 + 70 + 6,
written form = eight hundred seventy six.
• expanded notation or form is a way of writing numbers to show place value.
• the value of a digit depending on its place in a number.
• in the decimal system, each place is 10x bigger than the place to its right.
• the decimal system uses 10 digits to show all numbers 0,1,2,3,4,5,6,7,8,9
by using place value and a decimal point to separate
whole numbers from decimal fractions.
• standard form is the usual way of writing numbers in decimal notation, i.e.
standard form = 876, expanded form = 800 + 70 + 6,
written form = eight hundred seventy six.
• expanded notation or form is a way of writing numbers to show place value.
Number line
• a line marked with numbers which is useful as a visual aid for
calculating and showing relationships between values.
jump strategy
• jumping along an unmarked number line using
place value to work out a calculation,
numbers are written as required.
EXAMPLES:
• a line marked with numbers which is useful as a visual aid for
calculating and showing relationships between values.
jump strategy
• jumping along an unmarked number line using
place value to work out a calculation,
numbers are written as required.
EXAMPLES:
Rounding Numbers
Rounding means making a number simpler but keeping its value close to what it was. The result is less accurate, but easier to use.
Example: 73
rounded to the nearest ten is 70, because 73 is closer to 70 than to 80.
EXAMPLES:
Rounding Rules
more than 5 > up
less than 5 < down
1. Look at the digit in the place value to be rounded to.
2. Increase it by 1 if the digit to the right of it is 5 or more.
3. Leave it the same if the digit to the right of it is less than 5.
4. Remove everything to the right of the digit.
Example:
Round 626 to the nearest tens place
626=630
Round to the nearest hundreds place
626=600
Rounding means making a number simpler but keeping its value close to what it was. The result is less accurate, but easier to use.
Example: 73
rounded to the nearest ten is 70, because 73 is closer to 70 than to 80.
EXAMPLES:
Rounding Rules
more than 5 > up
less than 5 < down
1. Look at the digit in the place value to be rounded to.
2. Increase it by 1 if the digit to the right of it is 5 or more.
3. Leave it the same if the digit to the right of it is less than 5.
4. Remove everything to the right of the digit.
Example:
Round 626 to the nearest tens place
626=630
Round to the nearest hundreds place
626=600