Any number multiplied by 0 equals 0. Any number multiplied by 1 equals itself. Any number multiplied by 5 equals a number that ends with 0 or 5. Any number that is multiplied by an even number results in an even number. For example: 7 x 6 = 42 and 5 x 4 = 20.
Any number whose digits add up to a number divisible by 3 is evenly divisible by 3. Take the example 6,522: add 6 + 5 + 2 + 2 = 15 and then 1 + 5 = 6, which is divisible by 3. (6,522 divided by 3 equals 2,174.) Any number that is even and is divisible by 3 is also divisible by 6. The example 6,522 is even and divisible by 3. (6522 divided by 6 equals 1087.)
Typically, the 9's table is the hardest multiplication column for students to learn. An easy trick to figure out what 9 times any number is involves counting with your fingers. Spread your hands out in front of you. Assign a number to each finger and thumb, starting with the little finger of the left hand, which would be 1. Fold down the finger assigned to whichever number you want to multiply the 9 by. The number of fingers to the left of the bent finger is the answer's ten's position, and the number to the right is the one's position. For example, if you want to multiply 9 by 6, fold down the number 6 digit, which is the thumb of the right hand. There are five fingers to the left of the folded thumb, indicating 50, and there are four fingers to the right of the folded thumb, indicating 4. Thus, the answer to 9 times 6 is 54.
Make addition in your head easier by breaking down multi-digit numbers into manageable parts and then adding them. For example, to add 362 plus 589, break down the 589 to 500 + 89. Add the 500 to the 362 to get 862. The 89 can be managed in two ways: either you can break it into 80 + 9, adding the 80 to the 862 with a result of 942 and then add the 9 to that, resulting in 951. Or you can round off the 89 to 90, keeping note that you are working with one extra, and adding 90 to 862 to get 952 then subtracting the extra 1 to get 951.