# MATH

• WELCOME TO MATH!

Today we will begin studying the concept of Measurement :)

Please look at the markings on the ruler on page 260.

We know that a standard ruler is 12 inches in length.
You can see that each measurement of one inch is numbered in red on page 260. So, on a 12-inch ruler, there will be 12 markings indicating the location of each of the 12 inches.

Now, looking at the ruler on page 260, see if you can locate where the halfway mark is between the one inch markings.
The 1/2-inch markings are written as 1/2 and are printed in green.

There are TWO 'half inches' in every inch. (The green 1/2-inch mark divides the length of one inch into exactly two equal halves.)

►As you move along the ruler, you can see that the first green 1/2 mark measures
one half of an inch, or 1/2 inch.
This is because it is located half way between the left end of the ruler (or zero) and the 1 inch mark.
►As you move along the ruler, the next green 1/2 mark is located halfway between the '1 inch' mark and the '2 inch' mark. This indicates the point of
1 1/2 inches. (One whole inch plus 1/2 inch.)
►As you move along the ruler, the next green 1/2 mark is located halfway between the '2 inch' mark and the '3 inch' mark. This indicates the point of
2 1/2 inches. (Two whole inches plus 1/2 inch.)
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Now let's look at the 'One Quarter of an Inch,' or 1/4 inch.
It is represented on the ruler in the color blue.
Each inch is divided into four equal sections. Each of those sections is called a Quarter Inch or 1/4 inch. Looking at the ruler on page 260, the first 1/4 inch marking is located halfway between the left edge of the ruler (or zero) and the 1/2-inch mark. This indicates the point of
one quarter of an inch or 1/4 inch.
►As you move along the ruler, the next 1/4-inch mark would be in exactly the same spot as the 1/2-inch mark. Rather than marking the spot with both a blue 1/4- and a green 1/2-inch symbol, we will just leave it as 1/2-inch.
If we did mark it in the blue 1/4-inch symbol, it would look like this:
two quarters of an inch or 2/4 inch.
In truth, 2/4 inch is the same as 1/2 inch; so we will leave it marked as 1/2 inch.
►As you move along the ruler, the next 1/4-inch mark is located halfway between the 1/2-inch mark and the 1-inch mark.  This indicates the point of
three quarters of an inch or 3/4 inch.

► As you move along the ruler, the next 1/4-inch mark would be in exactly the same spot as the 1-inch mark. Rather than marking the spot with both a blue 1/4- and a red 1-inch symbol, we will just leave it as 1 inch.
If we did mark it in the blue 1/4-inch symbol, it would look like this:
four quarters of an inch or 4/4 inch.
In truth, 4/4 inch is the same as 1 inch. (4 fourths = one whole)

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NEXT: Please look at the green crayon on page 260.
They have drawn red dotted lines from each end of the crayon to the ruler below it.
IMPORTANT: Notice that they have lined up the left edge of the crayon with the left edge of the ruler (or zero).

Q: How long is the green crayon?
A: The crayon is about 3 1/2 inches long.

Q: How long is the pink eraser on page 260?
A: The eraser is about 1 1/4 inches long.

YOU'VE GOT IT!