Using shorter method, find:

(i) 3246 + 9999

(ii) 7501 + 99999

(iii) 5377 - 999

(iv) 25718 - 9999

(v) 123 × 999

(vi) 203 × 9999

Without using a diagram, find:

(i) 9^th square number

(ii) 7^th triangular number

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 = …….

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 = …….