Concept 2 of 7
Arrays: Rows and Columns
Today's big idea
An array lines things into equal rows, so rows × columns gives the total.
2 rows of 5 is 2 × 5 = 10, without counting each dot.
How it works
👀 What's going on?
An egg tray, a chocolate bar, a window with panes — they all line things up in neat rows and columns. That tidy shape has a name: an array, and it makes multiplying easy.
💡 Here's the trick
Look at the dots above, lined up in rows and columns. Every row has the same number, so you can multiply the number of rows by the number in each row. A 2-by-5 array means 2 × 5.
🪄 How to do it
- 1.Count the number of rows.
- 2.Count how many are in one row (the columns).
- 3.Multiply rows × columns to get the total.
✍️ Try it
- 1.2 rows of 5 dots — how many dots?
- 2.3 rows of 3 dots — how many dots?
2 rows of 5 is 2 × 5 = 10. And 3 rows of 3 is 3 × 3 = 9.
⚠️ Watch out
Count a row and a column, not every single dot. The whole point of an array is that you never have to count them one by one.
🌟 Why this matters
Arrays show up in egg boxes, seating plans and calendars. Seeing rows and columns as a multiplication makes big counts quick.
Exam tip: Rows × columns — and turning the array sideways gives the same total.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“An array has 3 rows with 4 dots in each row. How many dots?”
- 1
Count rows and columns
3 rows, 4 in each.
- 2
Rows × columns
3 × 4 = 12
- 3
Answer ✓
12 dots
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
An array is rows and columns. Count the rows, count the columns, then multiply.
ARRAY · ROUND 1 OF 3
2 rows of 5 = 2 × 5
How many dots in all?
Quick check
✅ VERIFICATION
An array has 3 rows with 4 dots in each row. How many dots altogether?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Times Tables
5 × 3 = 5, 10, 15.