An array is a set of objects arranged in equal rows and columns, like eggs in a box or chairs in a hall. Arrays help us count quickly.
Instead of counting one by one, count the rows and how many are in each row. 3 rows of 4 is 4 + 4 + 4, which is 12. You can also write it as 3 × 4 = 12. Turning the array round gives 4 rows of 3, which is still 12.
Worked example
There are 5 rows of chairs with 3 chairs in each row. How many chairs?
- Add 3 five times: 3, 6, 9, 12, 15.
- That is 5 × 3.
Answer:15 chairs
Key words
- array
- objects in equal rows and columns
- row
- a line going across
- column
- a line going up and down
Practise this
New questions every time.
Common Core-referenced: 2.OA.C.4