Multiplication of 2 two-digit numbers
Multiplication of 2 two-digit numbers where the first digit of both the numbers are same and the last digit of the two numbers sum to 10 Example To calculate 56 x 54 Multiply 5 by 5+1. So, 5 x 6 = 30. Write down 30. Multiply together the last digits: 6 x 4 = 24. Write down 24. The product of 56 and 54 is thus 3024. Multiplication of two numbers that differ by 2 (This trick only works if you have memorized or can quickly calculate the squares of numbers. When two numbers differ by 2, their product is always the square of the number in between these numbers minus 1. Example 18 x 20 =( 19 x 19) - 1 = 361 - 1 = 360 25 x 27 = (26 x 26) - 1 = 676 - 1 = 675 49 x 51 = (50 x 50 ) - 1 = 2500 - 1 = 2499 Multiplication of two numbers that differ by 4 (This trick only works if you have memorized or can quickly calculate the squares of numbers. If two ...