- #1

Logger

- 28

- 0

OP warned about not using the homework template

My 10 year old daughter was given this maths puzzle and I'm sure to you guys it would be pretty easy.

You have 5 numbers 1,2,3,4,5

Ho many possible combinations are there possibe for 1 digit combos,2 digit combos, 3 digit combos, 4 digit combos, and 5 digit combos. The numbers cannot repeat at any time and you cannot have the reverse of the numbers also (e.g 345 and 543 as same 3 numbers used in this 3 digit combo.)

For single digit combos there is onviously only 5 combos 1-5 (5)

For 5 digit combos there is only one combination 1-5 (1) as any other combo still uses the same 5 numbers

I thought using 5*4*3*2*1 / 4+3+2+1 = (12) would be the correct answer for the 4 digit combos

and that 5*4*3*2*1 / 3 +2 +1 = (20) would be correct for 3 digit combos and that 5*4*3*2*1 / 2+1 = (40) for 2 digit combos.

So total combos 5 + 40 + 20 + 12 + 1 = 78 possible combos would be correct but it's not.

What is the correct answer and can you explain how it is done.

Thanks in advance

You have 5 numbers 1,2,3,4,5

Ho many possible combinations are there possibe for 1 digit combos,2 digit combos, 3 digit combos, 4 digit combos, and 5 digit combos. The numbers cannot repeat at any time and you cannot have the reverse of the numbers also (e.g 345 and 543 as same 3 numbers used in this 3 digit combo.)

For single digit combos there is onviously only 5 combos 1-5 (5)

For 5 digit combos there is only one combination 1-5 (1) as any other combo still uses the same 5 numbers

I thought using 5*4*3*2*1 / 4+3+2+1 = (12) would be the correct answer for the 4 digit combos

and that 5*4*3*2*1 / 3 +2 +1 = (20) would be correct for 3 digit combos and that 5*4*3*2*1 / 2+1 = (40) for 2 digit combos.

So total combos 5 + 40 + 20 + 12 + 1 = 78 possible combos would be correct but it's not.

What is the correct answer and can you explain how it is done.

Thanks in advance