Compare & Order Decimal Numbers
You need to know the following symbols:
1. < means "less than"
2. > means "greater than"
3. = means "equal to"
Align the ones digit for the numbers. Compare the place value for each digit starting from the left. Find the first
difference, the number with the largest digit is the largest number.
Example: Order the numbers 57.41 and 57.53
57.41
57.53
The tenths digit is the first difference. Since 5 is larger than 4, the number 57.53 is larger than the number 57.41
MEAN
Mean is the average value of all data in a set. Add up the numbers then divide by the number of values in the set
to find the mean.
Example: Find the mean of the following: { 66, 72, 83, 89 }
Mean =
66 + 72 + 83 + 89
4
Mean =
310
4
Mean =
77.5
MEDIAN
The median is the value that has exactly half the data above it and half below it. To find the median, order the
numbers from smallest to largest. The middle number is the median. (If there is an even number of data values,
the median is the average of the middle two values.)
Example: Find the median of the following: { 65, 72, 81, 83, 89 }
Median = the middle number from smallest to largest
Median =
81
MODE
The mode is the number that appears most often in the set.
Example: Find the mode of the following: { 65, 65, 71, 72, 81, 83, 83, 83, 89 }
Mode = the number that appears most often
Mode =
83
RANGE
The range is the difference between the smallest and largest numbers in the set.
Example: Find the range of the following: { 65, 65, 71, 72, 81, 83, 83, 83, 89 }
Range = difference between the smallest and largest numbers
Range = 89 – 65
Range =
24
Dividing a Three Digit Number by a One Digit Number
Example - Divide 512 by 8.
The first number of the dividend (5) is less than 8. So, take the first two numbers of the dividend (51)
and determine how many times 8 will go into 51.
8 × 6 = 48 and 8 × 7 = 56
Thus, 8 will go into 51 six times. Place the 6 above the division bracket over the 1 from the 51.
Multiply the 6 by 8 and place the result below the 51 of the dividend.
Draw a line under the 48 and subtract it from 51 (51 - 48 = 3). Bring down the 2 from the 512 and place
it to the right of the 3.
Determine how many times 8 will go into 32 and place the answer above the division bracket and to the
right of the six.
Multiply the 4 by the 8 and place the result below the 32. Subtract 32 from the 32.
There are no more numbers in the dividend to bring down next to the 0. Therefore, 512 divided by 8
is 64.