## Thursday, 19 September 2013

### Create Multiplication Table For 5 And 7 Easily At Any Time

In Chapter 4. Multiplication Table For 5 And 7, Key Numbers For Week Days I have already explained how to create multiplication table for 5 on time. But in this post I will explain it again in the easier form so that you can create the table for 5 more quickly.

STEP 1. Create a table as shown below

 5 x 0 0 5 x 1 5 5 x 2 0 5 x 3 5 5 x 4 0 5 x 5 5 5 x 6 0 5 x 7 5 5 x 8 0 5 x 9 5 5 x 10 0

Here, first column contains multiplication i.e. 5 x a number (0-10). In second column we have only 5 as the last digit in alternate rows whereas in 3rd column we have only 0 as the last digit in alternate rows.

STEP 2. Put numbers in order 0, 0, 1, 1, 2, 2 and so on in alternate rows and before existing digit. So, we get-

 5 x 0 00 5 x 1 05 5 x 2 10 5 x 3 15 5 x 4 20 5 x 5 25 5 x 6 30 5 x 7 35 5 x 8 40 5 x 9 45 5 x 10 50

And multiplication table for 5 is ready! :)

Now let's move to our important multiplication table i.e. for 7. It is so easy and interesting, you will surely enjoy while creating it.

STEP 1. Create a table as shown below

 7 4 1 8 5 2 9 6 3

Here we have entered the numbers from 1 to 9 in top to bottom and right to left order. Let's say these are last digits of our multiplication results.

STEP 2. Create another table as shown below

 0 1 2 2 3 4 4 5 6

Let's say these are first digits of our multiplication results.

STEP 3. Merge two tables and we get-

 07 14 21 28 35 42 49 56 63

In another way-

 7x1=07 7x2=14 7x3=21 7x4=28 7x5=35 7x6=42 7x7=49 7x8=56 7x9=63

Also we know, 7 x 0 =00 and 7 x 10 =70. This is the multiplication table from 7 x 0 till 7 x 10. Now we will see for 7 x 11 till 7 x 20.

First table will remain the same i.e.

 7 4 1 8 5 2 9 6 3

Second table will be changed. We had left second table at 6 in STEP 2. So this time we will start from 7.

 7 8 9 9 10 11 11 12 13

Merging two tables will give-

 7x11=77 7x12=84 7x13=91 7x14=98 7x15=105 7x16=112 7x17=119 7x18=126 7x19=133

An 7 x 20 =140. That is to it! Now you can surely create multiplication table for 7 on time.. :)