Glossary: Terms Starting with O
23 definitions in Mathematics with links to the lessons that teach each word.
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All terms starting with O
object
MathsFrom Grade 1
A thing you can see and touch.
Learn it in: Identifying shapes in everyday life (Grade 1), Identifying shapes (Grade 2)
objects
MathsFrom Grade 1
Real things you can touch, like stones or seeds.
Learn it in: Addition using objects (Grade 1)
obtuse angle
MathsFrom Grade 3
Bigger than a right angle but less than a straight line.
Learn it in: Introduction to other angles (Grade 3)
odd
MathsFrom Grade 2
Has one left over when put in pairs.
Learn it in: Odd and even numbers (Grade 2), Prime numbers (Grade 4)
one-to-one
MathsFrom Grade 1
Saying one number for each object, once.
Learn it in: Counting objects from 0–10 (Grade 1)
ones
MathsFrom Grade 1
Single things. The ones digit shows how many.
Learn it in: Tens and ones (Grade 1), Grouping objects into tens (Grade 1), Understanding ones (Grade 1)
operation
MathsFrom Grade 2
Adding or subtracting.
Learn it in: Two-step word problems (Grade 2), Multistep problems (Grade 4), Numerical expressions (Grade 5)
opposite
MathsFrom Grade 1
Does the reverse.
Learn it in: Relationship between addition and subtraction (Grade 1), Introduction to integers (Grade 6), Positive and negative numbers (Grade 6)
order
MathsFrom Grade 1
Putting things one after another in a rule.
Learn it in: Ordering numbers (Grade 1), Ordering numbers (Grade 1), Comparing lengths (Grade 1)
order of operations
MathsFrom Grade 5
Rules for the sequence of steps.
Learn it in: Order of operations (Grade 5), Order of operations (Grade 5), Evaluating expressions (Grade 6)
ordered pair
MathsFrom Grade 5
(x, y).
Learn it in: Plotting points (Grade 5), Plotting points in four quadrants (Grade 6)
origin
MathsFrom Grade 5
The point (0, 0).
Learn it in: Coordinate grids (Grade 5), Coordinate plane (Grade 6)
outlier
MathsFrom Grade 6
Far-out value.
Learn it in: Dot plots (Grade 6), Range (Grade 6), Interpreting distributions (Grade 6)
output
MathsFrom Grade 5
What comes out.
Learn it in: Rules and relationships (Grade 5), Number relationships (Grade 6)
o’clock
MathsFrom Grade 1
The exact hour, like 3 o’clock.
Learn it in: Reading time to the hour (Grade 1)