Ads
related to: mental math multiplication by 2 digit numbers
Search results
Results From The WOW.Com Content Network
If the answer is greater than a single digit, simply carry over the extra digit (which will be a 1 or 2) to the next operation. The remaining digit is one digit of the final result. Example: Determine neighbors in the multiplicand 0316: digit 6 has no right neighbor; digit 1 has neighbor 6; digit 3 has neighbor 1
If one has a two-digit number, take it and add the two numbers together and put that sum in the middle, and one can get the answer. For example: 24 x 11 = 264 because 2 + 4 = 6 and the 6 is placed in between the 2 and the 4. Second example: 87 x 11 = 957 because 8 + 7 = 15 so the 5 goes in between the 8 and the 7 and the 1 is carried to the 8.
To multiply two numbers with n digits using this method, one needs about n 2 operations. More formally, multiplying two n-digit numbers using long multiplication requires Θ(n 2) single-digit operations (additions and multiplications).
With the chisanbop method it is possible to represent all numbers from 0 to 99 with the hands, rather than the usual 0 to 10, and to perform the addition, subtraction, multiplication and division of numbers. [4] The system has been described as being easier to use than a physical abacus for students with visual impairments. [5]
Adding ten 10-digit numbers, 7 minutes Winner: Yuki Kimura (Japan) Multiplying two 8-digit numbers, 10 minutes Winner: Lee Jeonghee (South Korea) Calendar Calculations, one minute, random dates from the years 1600–2100 Winner: Georgi Georgiev (Bulgaria), 66 correct results, world cup record; Square Roots from 6-digit numbers, 10 minutes
Mental subtraction 2: 12 "Nine Nits is all there's Room For" Addition and subtraction less than 10,000 3: 13 "Breaking up is Easy to Do" Multiplication 4: 14 "You Ain't Nothing but a Houndred" Multiplication of 3-digit numbers by single digits 5: 15 "Dividing we Stand" Dividing 3-digit numbers by 2-digit numbers 6: 16 "Double Digit Dating"