-1
A 3 or 4 digit number.
Multiplication in general is important; not just 2-digit numbers.
1
If multiplying 3 digit numbers with 2 digit numbers. For example; 345 x 92= First you will start with 2 by multiplying it by 5 then carry the 1 above the 4 then multiply the "2" with 4 then add the number on-top of the 4 which is 1 and it will give you 9. 4 x 2= 8+1=9. Then times the 2 by 3 which is 6. That is not your answer, yet. 690 plus the amount you get by multiplying 9 by every number, 5 then carry the number, 4 times 9, plus the number above it, then carry the 3 on top of the 3. Then add your total to 690 or what ever your equation is.
-1
A 3 or 4 digit number.
What is multiplying 2-Digit by 2-Digit numbers
6
Multiplication in general is important; not just 2-digit numbers.
1
If multiplying 3 digit numbers with 2 digit numbers. For example; 345 x 92= First you will start with 2 by multiplying it by 5 then carry the 1 above the 4 then multiply the "2" with 4 then add the number on-top of the 4 which is 1 and it will give you 9. 4 x 2= 8+1=9. Then times the 2 by 3 which is 6. That is not your answer, yet. 690 plus the amount you get by multiplying 9 by every number, 5 then carry the number, 4 times 9, plus the number above it, then carry the 3 on top of the 3. Then add your total to 690 or what ever your equation is.
There are 28706 such combinations. 5456 of these comprise three 2-digit numbers, 19008 comprise two 2-digit numbers and two 1-digit numbers, 4158 comprise one 2-digit number and four 1-digit numbers and 84 comprise six 1-digit numbers.
There are 9 1-digit numbers and 16-2 digit numbers. So a 5 digit combination is obtained as:Five 1-digit numbers and no 2-digit numbers: 126 combinationsThree 1-digit numbers and one 2-digit number: 1344 combinationsOne 1-digit numbers and two 2-digit numbers: 1080 combinationsThat makes a total of 2550 combinations. This scheme does not differentiate between {13, 24, 5} and {1, 2, 3, 4, 5}. Adjusting for that would complicate the calculation considerably and reduce the number of combinations.
1
Highest 2-digit number = 99 Highest 1-digit number = 9 Highest possible sum from 2, 2-digit numbers = 198 Highest possible sum from 2, 1-digit numbers = 18
There is no such ratio that applies for all single-digit and double-digit integers.