Mathematics
Observe the following pattern and fill in the blanks:
1 × 9 + 1 = 10
12 × 9 + 2 = 110
123 × 9 + 3 = 1110
1234 × 9 + 4 = …….
12345 × 9 + 5 = …….
Related Questions
Without using a diagram, find:
(i) 9th square number
(ii) 7th triangular number
(i) Can a rectangular number be a square number?
(ii) Can a triangular number be a square number?
Observe the following pattern and fill in the blanks:
9 × 9 + 7 = 88
98 × 9 + 6 = 888
987 × 9 + 5 = 8888
9876 × 9 + 4 = …….
98765 × 9 + 3 = …….
Look at the following figures made up of dots:

These figures show the arrangement of the numbers 2 × 3 or 3 × 2; 2 × 4 or 4 × 2 i.e. the numbers 6 and 8.
The numbers 6 and 8 are called rectangular numbers. Can you write two more rectangular numbers?