Matrices & determinants
Order, multiplication, transpose, determinants and inverses.
Learn with Kutty
Go one screen at a time. Press Next when you are ready. Tap 🔊 Read to me to listen.
A matrix is a table of numbers. To multiply, go along a row and down a column.
Look: Top-left answer: 1 × 5 + 2 × 7 = 19.
✏️ Your turn!
Type your answer and press Check. Kutty will tell you if it is right.
1[1 2] × [3, 4] (column) = ?
2How many rows in a 2 × 3 matrix?
3Determinant of [[3, 1], [4, 2]]? (ad − bc)
! Careful!
✗Multiplying box by box.
✓Row × column, then add.
✗Thinking A × B = B × A.
✓Order usually matters for matrices.
See the whole lesson on one page
A matrix is a table of numbers. To multiply, go along a row and down a column.
Each answer box = (row of the first) × (column of the second), multiplying pairs and adding them up.
Think of it like thisA bill: quantities in a row, prices in a column. Multiply each pair and add: that is the total — one matrix multiplication.
Solved together
Ravi buys 2 pens and 3 books. A pen costs ₹10 and a book ₹40. Use a row × column to find the total.
Row of quantities, column of prices.
Multiply pairs and add.
2 × 10 + 3 × 40 = 20 + 120 = 140
AnswerTotal ₹140.
For older learners and grown-ups: a little more
The determinant of [[a, b], [c, d]] is ad − bc. If it is not 0, the inverse is (1/det)[[d, −b], [−c, a]], which solves AX = B as X = A⁻¹B. E.g. 2x + 3y = 8, x + 2y = 5 gives x = 1, y = 2.
Now practise it
Kanakku makes new questions on matrices & determinants every time. It shows the working and gives a hint when you are stuck.