Learning to multiply 3's 6's 7's and 9's

3's 6's 7's and 9's are hard numbers to multiply.   There are complete tutoring agencies teaching math because of 3's 6's 7's and 9's

The series does not flow as easily as others.

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90

The numbers that are high lighted are the numbers on the 10 x 10 multiplication table that gives students the most problems.

I have my students figure out the series the series to 6 9 18 21 and 27 after they learn to multiply 2 4 5 8 10.  6 and 9 are pretty simple by this time so to complete the threes  18 21 and 27 need to be memorized. 3 x 6 =18 3 x 7 =21 and 3 x 9=27




If the student has learned the 2's 4's 5's 8's and 10's the table will be as follows after the student learns the 3's:

1 2 3 4 5 6 7 8 9 10 1 1 2 3 4 5 6 7 8 9 10 2 2 4 6 8 10 12 14 16 18 20 3 3 6 9 12 15 18 21 24 27 30 4 4 8 12 16 20 24 28 32 36 40 5 5 10 15 20 25 30 35 40 45 50 6 6 12 18 24 30 48 60 7 7 14 21 28 35 56 70 8 8 16 24 32 40 48 56 64 72 80 9 9 18 27 36 45 72 90 10 10 20 30 40 50 60 70 80 90 100

The next series is 6 and 36 42 and 54 are hard numbers for students.  6 x 6=36  6 x 7 = 42 6 x 9 = 54

	1	2	3	4	5	6	7	8	9	10
1	1	2	3	4	5	6	7	8	9	10
2	2	4	6	8	10	12	14	16	18	20
3	3	6	9	12	15	18	21	24	27	30
4	4	8	12	16	20	24	28	32	36	40
5	5	10	15	20	25	30	35	40	45	50
6	6	12	18	24	30	36	42	48	54	60
7	7	14	21	28	35	42		56		70
8	8	16	24	32	40	48	56	64	72	80
9	9	18	27	36	45	54		72		90
10	10	20	30	40	50	60	70	80	90	100

The next series is 9 and 7.  Memorize 9 x 7 =63 and 9 x 9= 81.  The 10 x 10 multiplication table is done.

Do plenty of exercises and you will have this constantly in your memory.