Sum-Average
- Find summation of 3-digits numbers made using 1, 2, & 3 and 4-digits numbers using 1, 2, 3, 4.
- Find summation of all possible numbers above 100,00, made using the digits 0, 2, 4, 6, 8.
- Sum of all possible numbers using 1, 2, 3, 4, each just once.
- Make the general formula to find sum of all possible numbers
- Average of 9-digit numbers made using 5 five times and 4 four times.
- Find sum of numbers greater than 10,000, using 1, 3, 5, 7, 9
- Find sum of all possible numbers, using 1, 3, 5, 7, 9
- 2!(1+2+3)(1+10+100) & 3!(1+2+3)1111
- 4!(0+2+4+6+8)(1+10+100+1000+10000)-3!(2+4+6+8)(1+10+100+1000)
- \(3! (1+2+3+4)(1111)+^3P_2 \times 10 \times 111+ ^3P_1 \times 10 \times 11 + 10\)
- \((n-1)! \times D \times \sum_{i=0}^n 10^i\); (D = Sum of digits, n = no. of digits in the numbers made)
- \(n=\frac{9!}{5!4!}, \bar X=\frac{}{n}\)
- All 5-digit numbers: 4!(1+3+5+7+9)11111=6666600
- 1, 2, 3, o4 4 digit numbers: 4!(1+3+5+7+9)11111+…