118
The 9 times table
Textbook: Part 3, lesson 111, pp. 84–85
GoalKnow the 9 times table; see that brackets change the value of an expression.
New words
the 9 times table · 9 ga ko‘paytirish jadvalibracket · qavstelephone · telefonprice · narx
Explanation
The 9 times table: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90. A nice pattern: the digits of each product add up to 9: 18 → 1 + 8, 27 → 2 + 7, 54 → 5 + 4. Brackets change the value of an expression: (9 × 9) − 1 = 80, but 9 × (9 − 1) = 72.
Worked examples
9 × 6 = 54 and 5 × 9 = 45.
(3 + 6) × 9 = 9 × 9 = 81, but 3 + (6 × 9) = 3 + 54 = 57.
Class activity
“The magic of 9”: children write the 9 times table, add the digits of each product and find that the sum is always 9. They can also check the table with their fingers.
Practice
1
9 × 6 = ?
54
2
One minute of an overseas call costs 9 thousand so‘m. How many thousand does 5 minutes cost?
45
3
Komila learns 9 new words a day. How many new words does she learn in a week (7 days)?
63
4
Malika is 8. Her grandmother is 9 times as old. How old is the grandmother?
72
5
(9 × 9) − 1 = ?
80
6
9 × (9 − 1) = ?
72