Comment by xigoi | Hacker News Reader

Top New Best Ask Show Jobs

Comment by xigoi | Hacker News Reader

Parent Full thread

How do you know that 800 × 3 = 2400 if you haven't learned multiplication tables?

(8+8+8)*100

Addition

8 x 3 = 24

8 x 300 = 2400

Add two zeros

I meant, how do you know 8 × 3 without a multiplication table?

Ah I see what you mean In my head, I do this:

8 + 8 = 16

16 + 8 = 24

Reply on news.ycombinator.com