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•If you have a hard mental maths sum e.g.25x48 you could use the halving and doubling method (as long as one of the numbers is even).
Step one
•You start by halving the 48 and doubling the 25.
•Like this 25x2=5048/2=24
Step two
•If you don’t want to do a sum like 50x24 you could do the same method again.
•Like this.
50x2=10024\2=12 50 x 24…25 x 48 =
Step three
•Finally, when you are happy - you do the sum in your head...
•Like this
100x12=1200
•So the answer is 1200
25 x 48 = 50 x 24 = 100 x 12 =
3) 100x12=1200so
25 x 48 = 12001) 25x2=5048/2=24
2) 50x2=10024\2=12
Here is a summary of the steps...
Starting with 25 x 48...
3) 55 x 6
1) 45 x 18
2) 35 x 24
Now you can have a go at these…
Click to continue…
3) 55 x 6 = 110 x 3 =
(11 x 3) x 10 = 330
1) 45 x 18 =90 x 9 =
(9 x 9) x 10=810 !
2) 35 x 24 = 70 x 12 =
(7 x 12) x 10=840 !
The answers…
I hope you enjoyed my show!
Remember to halve,
double and make use
of your times tables!
The end… (for now)!