Exercise 2.3
1. Study the pattern:
1 × 8 + 1 = 9 (1)
12 × 8 + 2 = 98 (2)
123 × 8 + 3 = 987 (3)
1234 × 8 + 4 = 9876 (4)
12345 × 8 + 5 = 98765 (5)
Write the next four steps. Can you find out how the pattern works?
2. Study the pattern:
91 × 11 × 1 = 1001 (1)
91 × 11 × 2 = 2002 (2)
91 × 11 × 3 = 3003 (3)
Write next seven steps. Check, whether the result is correct. Try the pattern for 143 × 7 × 1, 143 × 7 × 2 and so on.
3. How would we multiply the numbers 13680347, 35702369 and 25692359 with 9 mentally? What is the pattern that emerges.