Math Lesson 3 Instruction, page 2

Instruction 3-2

COMPARE AND ORDER POSITIVE AND NEGATIVE FRACTIONS, DECIMALS, MIXED NUMBERS
CA GR6 NS 1.1

There is more than one way to compare and order decimals.

Method A: Use a number line to compare 13.6 and 13.4.


13.4 is to the left of 13.6, 13.4 < 13.6
Method B: Example 1: Use place-value to compare 3.6 and 3.4.
Compare the tens.		Compare the ones.		Compare the tenths.
13.4	Think: 1 = 1	13.4	Think: 3 = 3	13.4	Think: 4 < 6
13.6		13.6		13.6	3.4 < 3.6

Example 2: Compare 5.39 and 5.36.
Compare the ones.		Compare the tenths.		Compare the hundredths.
5.36	Think: 5 = 5	5.36	Think: 3 = 3	5.36	Think 9 > 6
5.39	5.39	5.39		5.39	5.39 > 5.36

Example 3: Order from least to greatest:
0.234, 0.243, 0.245
Compare the hundredths.		Compare the thousandths.
0.234 0.243 0.245		0.243 0.245
From least to greatest:
0.234, 0.243, 0.245

Example 4:Order from greatest to least:
0.433, 0.471, and 0.474
0.433 0.471 0.474	0.471 0.474
From greatest to least:
0.474, 0.471, 0.433

To compare and order fractions and mixed numbers, you must first find the lowest common denominator of the fractions or mixed numbers that you are comparing. In order to find the lowest common denominator, you must find the least common multiple first.

The least common multiple of two or more whole number is the lowest whole number, greater than 0, that is a multiple of each of the numbers.

The lowest common denominator is the least common multiple of the denominators of two or more fractions.

Example 5: Find the least common multiple of 4 and 6.

List multiples of 4 and 6.

4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40	Think: 1 x 4 = 4; 2 x 4 = 8; 3 x 4 = 12;
		4 x 4 = 16; 4 x 5 = 20; 4 x 6 = 24
6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60	Think: 1 x 6 = 6; 2 x 6 = 12; 3 x 6 = 18;
		4 x 6 = 24; 5 x 6 = 30; 6 x 6 = 36