Question

2. Find an easy way to workout the answers.
(a) 19 x 21 =
(b) 29 x 31 =
(c) 39 x 41 =
(d) 49 x 51 =
(e) 69 x 71 =
(f) 89 x 91 =​

Answer 1

Answer:

1=399

2=899

3=1599

4=2499

5=4899

6=8009