Objects rarely end exactly on a number. Rulers have smaller marks for that.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Halves
The mark halfway between 3 and 4 is 3 and a half.
Fourths
Cut each unit into 4 and you can read quarters too.
This is why fractions matter
Real measurements land between whole numbers, so you need fractions to say them.
The marks between the numbers
A ruler marked in halves has one extra line between each pair of numbers. Marked in fourths, it has three. Those lines let you record a length that does not land on a whole number, such as 3 1/2 inches.
Reading between the numbers
Find the last whole number the object passes, then count the small marks after it. Two fourths past the 3 is 3 2/4, which is the same as 3 1/2. Equivalent fractions turn up here in an entirely practical setting.
Finer marks, finer measurement
The more marks a ruler has, the more precisely you can measure. But no ruler is exact — you are always saying which mark the object is nearest. Every real measurement is an approximation, and knowing that is part of measuring well.
Step 2: Try It Yourself
Tap and try it out.
inches
05
It starts at 0 and ends at 3, so it is 3 inches long.
Step 3: Watch an Example
One step at a time.
Watch Leo Read a Half
Leo measures a pencil that ends between the 3 and the 4.
- Step 1
He finds the last whole number the pencil passed: 3.
Step 4: Your Turn
Practice makes it stick.
Between Marks
Problem 1 of 2
An object ends halfway between 5 and 6 inches. How many fourths past the 5 is that?
fourths
Quarter Past
Problem 2 of 2
An object ends one fourth past the 4 inch mark. How many fourths past 4?
fourth
Read Between the Numbers
1 of 3
How many fourths make one half?
2 of 3
How many fourths are in one whole inch?
3 of 3
How many fourths are in 2 whole inches?
Step 5: Quick Check
Show what you know.
Question 1 of 2
How many fourths make three quarters?
Question 2 of 2
Why does a ruler have marks between the numbers?
What You Learned
- Rulers have marks between the whole numbers.
- Halves and fourths let you name a length in between.
- This is what fractions are for.