mathiscool
New member
- Joined
- Apr 15, 2013
- Messages
- 2
Hi,
I am new here. I would like to know if there are other methods of 2 digits by digits mental multiplication beside the ones below.
Here are some of my methods.
Method 1
78*47 = 7*4 is 28 , 8*7 is 56 therefore 2856 and 8*4 = 32 , 7*7 = 49 add 49+32 = 81
now add 2856
81
3666
Method 2
78*40 = 3120 , 78*7 = 546
thus add 3120
546
3666
I would appreciate it if you can pitch in some ideas the easiest and quickest way of mental multiplication.
Cheers
I am new here. I would like to know if there are other methods of 2 digits by digits mental multiplication beside the ones below.
Here are some of my methods.
Method 1
78*47 = 7*4 is 28 , 8*7 is 56 therefore 2856 and 8*4 = 32 , 7*7 = 49 add 49+32 = 81
now add 2856
81
3666
Method 2
78*40 = 3120 , 78*7 = 546
thus add 3120
546
3666
I would appreciate it if you can pitch in some ideas the easiest and quickest way of mental multiplication.
Cheers