ARRAY
Definition Of Array
An Array is an arrangement of a set of numbers or objects in rows and columns.
More About Array
An array is normally used to write multiplication and division number sentences.
A multiplication array can easily be expressed as a repeated addition.
A division array can easily be expressed as a repeated subtraction.
Examples of Array
The dots in the above figure are arranged in 4 rows and 7 columns. It can also be written as 7 × 4 = 7 + 7 + 7 + 7 = 28
The cubes in the above figure are arranged in 4 rows and 9 columns. It can also be written as 9 × 4 = 9 + 9 + 9 + 9 = 36.
Video Examples: How to Write Math Arrays : Principles of Math
Solved Example on Array
Ques: Greg shaded the cells on a grid to make a rectangle, as shown. Which number sentence could be used to determine the total number of cells shaded to make the rectangle?
Choices:
A. 4 × 6 = 24
B. 1 × 25 = 25
C. 5 × 6 = 30
D. 30 × 3 = 90
Correct Answer: C
Solution:
Step 1: On the grid shown, the rectangle is 5 rows wide with 6 cells shaded in each row and there are 30 cells shaded in all.
Step 2: Number of rows × Number of cells shaded in each row = Total number of cells that make the rectangle
Step 3: 5 × 6 = 30 [Substitute the values.]
Step 4: So, the number sentence that could be used to determine the total number of cells shaded to make the rectangle is 5 × 6 = 30.
Quick Summary
- Arrays visually represent multiplication.
- Arrays can be used to represent repeated addition.
- Arrays can be used to represent repeated subtraction (division).
🍎 Teacher Insights
Use manipulatives like counters or blocks to build arrays. Relate arrays to real-world objects like egg cartons or seating arrangements.🎓 Prerequisites
- Basic counting
- Understanding of rows and columns
Check Your Knowledge
Q1: Which number sentence represents an array with 3 rows and 5 columns?
Q2: How many dots are there in an array of 4 rows and 6 columns?
Frequently Asked Questions
Q: What is the difference between a row and a column?
A: A row runs horizontally, while a column runs vertically.
Q: How can an array help with division?
A: By visually representing how many times a number can be subtracted from another.