Numbers are mathematical objects used to count, measure, and label. They can be used to represent quantities, order, and patterns.

There are several types of numbers, including:

- Whole Numbers: 0, 1, 2, 3, ...
- Integers: ... -3, -2, -1, 0, 1, 2, 3, ...
- Rational Numbers: Numbers that can be expressed as a fraction, such as 1/2, 3/4, 5/2, etc.
- Real Numbers: All rational and irrational numbers, such as √2, π, etc.

Numbers have various properties, including:

- Commutative Property: a + b = b + a
- Associative Property: (a + b) + c = a + (b + c)
- Distributive Property: a * (b + c) = a * b + a * c
- Identity Property: a + 0 = a, a * 1 = a
- Inverse Property: a + (-a) = 0, a * (1/a) = 1

Numbers are made up of digits, and the position of each digit in a number determines its value. This is known as place value.

For example, in the number 3,215, the digit 3 is in the thousands place, the digit 2 is in the hundreds place, the digit 1 is in the tens place, and the digit 5 is in the ones place.

Basic number operations include addition, subtraction, multiplication, and division. These operations follow specific rules and properties.

Prime numbers are numbers greater than 1 that have no positive divisors other than 1 and themselves. Composite numbers are numbers that have more than two positive divisors.

Even numbers are integers that are divisible by 2, while odd numbers are integers that are not divisible by 2.

Study GuideMore Multiplication Activity LessonMultiplication Stars Worksheet/Answer key

More Multiplication Worksheet/Answer key

More Multiplication Worksheet/Answer key

More Multiplication

Number and Operations (NCTM)

Compute fluently and make reasonable estimates.

Develop fluency in adding, subtracting, multiplying, and dividing whole numbers.

Select appropriate methods and tools for computing with whole numbers from among mental computation, estimation, calculators, and paper and pencil according to the context and nature of the computation and use the selected method or tools.

Algebra (NCTM)

Use mathematical models to represent and understand quantitative relationships.

Model problem situations with objects and use representations such as graphs, tables, and equations to draw conclusions.

Grade 4 Curriculum Focal Points (NCTM)

Number and Operations and Algebra: Developing quick recall of multiplication facts and related division facts and fluency with whole number multiplication

Students use understandings of multiplication to develop quick recall of the basic multiplication facts and related division facts. They apply their understanding of models for multiplication (i.e., equal-sized groups, arrays, area models, equal intervals on the number line), place value, and properties of operations (in particular, the distributive property) as they develop, discuss, and use efficient, accurate, and generalizable methods to multiply multi-digit whole numbers. They select appropriate methods and apply them accurately to estimate products or calculate them mentally, depending on the context and numbers involved. They develop fluency with efficient procedures, including the standard algorithm, for multiplying whole numbers, understand why the procedures work (on the basis of place value and properties of operations), and use them to solve problems.