First Grade Math Picture Glossary - First Grade Mathematics

Welcome to your First Grade Math Picture Glossary, an illustrated reference handbook containing all the essential words, concepts, symbols, and mathematical terms you have learned this year. When mathematicians talk with one another, they use precise vocabulary so their ideas are clear and exact. Whenever you forget what a term means while reading or solving problems, you can flip to this glossary to see its definition, look at an ASCII diagram, and remember how it works. In this chapter, you will find comprehensive explanations of the most important terms from numbers, operations, geometry, measurement, and data.

Numbers and Place Value Terms

Here are the fundamental terms used to describe our number system and how quantities are built.

Number Concepts:
- DIGIT: One of the ten basic symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) used to write all numbers.
- PLACE VALUE: The value of a digit depending on where it sits in a number. In 43, 4 is worth 40.
- TEN: A unit made of exactly 10 single ones bundled together into 1 rod.
- ONES: The single units in the rightmost column of a place-value chart.
- EXPANDED FORM: Writing a number to show the value of each part (e.g., 50 + 6 = 56).

The Rod and Unit Visual

A unit is 1 single cube: [#]. A rod is 10 cubes connected together: [#|#|#|#|#|#|#|#|#|#]. Ten units trade for one rod!

Operations and Algebra Terms

These terms describe the actions we perform when combining, separating, and comparing quantities.

Operation Vocabulary:
- ADDEND: One of the numbers being added together. In 4 + 5 = 9, 4 and 5 are addends.
- SUM: The total answer obtained by adding numbers together.
- MINUEND: The starting whole number in a subtraction problem before removal (e.g., 9 in 9 - 4 = 5).
- SUBTRAHEND: The number being taken away in a subtraction problem (e.g., 4 in 9 - 4 = 5).
- DIFFERENCE: The answer in a subtraction problem representing the amount left or the gap.
- EQUAL SIGN (=): The symbol of balance showing that both sides have the exact same value.
- FACT FAMILY: A group of related addition and subtraction facts using the same three numbers.

The Balance Scale Model

Equality means level balance: [ Left Pan ] = [ Right Pan ]. If 6 + 2 sits on the left pan and 8 sits on the right pan, the scale is perfectly balanced!

Geometry and Measurement Terms

These terms describe flat shapes, solid figures, length, time, and money.

Shapes and Measurement:
- 2D SHAPE: A completely flat geometric figure having length and width, but no depth.
- 3D SOLID: A solid object with length, width, and height that takes up physical space.
- VERTEX (Vertices): The corner point where two sides of a 2D shape or three edges of a 3D solid meet.
- HALF: One of two equal shares that together compose one whole shape (2 halves = 1 whole).
- FOURTH (Quarter): One of four equal shares that compose one whole shape (4 fourths = 1 whole).
- HOUR HAND: The short, slow-moving hand on an analog clock that points to the hour.
- MINUTE HAND: The long, fast-moving hand on an analog clock that points to the minutes.
- DIME: A small silver coin worth 10 cents (10¢).
- NICKEL: A thick silver coin worth 5 cents (5¢).
- PENNY: A reddish-brown copper coin worth 1 cent (1¢).
- QUARTER: A large silver coin worth 25 cents (25¢).

Practice Exercises

Exercise 1: What is the mathematical difference between an "addend" and a "sum"?

Exercise 2: Define the word "vertex" and state how many vertices a triangle has and how many a rectangle has.

Exercise 3: What does the word "half" mean in geometry, and how many halves are needed to make one complete whole?

Exercise 4: Which coin is worth 10 cents, and which coin is worth 5 cents?

Solutions and Explanations

Solution to Exercise 1: An addend is one of the individual numbers (parts) that are joined together in an addition problem, while the sum is the final total (whole) result of adding those numbers.

Solution to Exercise 2: A vertex is a corner point where straight sides or edges meet. A triangle has 3 vertices, and a rectangle has 4 vertices.

Solution to Exercise 3: A half is one of two equal shares of a whole that has been partitioned into two identical parts. Exactly two halves make one complete whole.

Solution to Exercise 4: A dime is worth 10 cents (10¢), and a nickel is worth 5 cents (5¢).