The 3
×
table
1
2
3
4
5
6
7
8
9
10
×
×
×
×
×
×
×
×
×
×
3
3
3
3
3
3
3
3
3
3
=
=
=
=
=
=
=
=
=
=
3
6
9
12
15
18
21
24
27
30
Have a look at these timesavers.
There’s a clever trick you can use
to find out if a number is in the 3 × table. Add up the digits
of the number you want to find out about - this is called finding the digit sum.
If the digit
sum is 3, 6, or 9
,
then you know that it’s in the 3 × table.
Let’s look at
15.
The digits are
1
and
5
.
Add those together and you get
6
.
1 + 5 = 6.
So 15 is in the 3 × table.
Now let’s look at a bigger number:
156
.
The digits are
1, 5 and 6
.
Add 1 + 5 + 6 and you get
12.
Now add up the digits 1 and 2 and you get 3.
So 156 is in the 3 × table.
This trick always works, even with a really big number like 12,346,911.
Just add up the digits:
1 + 2 + 3 + 4 + 6+ 9 + 1 + 1 = 27
then add 2 + 7 = 9
So 12,346,911 is in the 3 × table.