1=(4-3)÷(2-1)2=(4+2)-(3+1)3=3×2-4+14=4÷2+3-15=12-(3+4)6=(3×4)×1÷27=1+(3×4)÷28=4+2-1+39=41-3210=(1×4)+(3×2)11=42-3112=(4×3)×(2-1)13=12-3+414=(3×4)×1+215=(3×4)+1+216=2(3+4+1)17=3(4+2)-118=32-1419=14+3+220=4(2+3×1)21=(1+2)×(3+4)22=34-1223=4(3×2)-124=1×3×4×225=(4+1)×(3+2)26=2(4×3+1)27=1×3+2428=4(2×3+1)29=1+32-430=2(1+4)×331=34-1-232=2(1+3)×433=21+3×434=34(2-1)35=4+32-136=4(2+1)×337=14+2338=42-1-339=42-(3×1)40=43-1-241=43-(2×1)42=43-2+143=43(2-1)44=2+3(14)45=12×4-346=41+2+347=41+(3×2)48=24(3-1)49=I Don't Know50=13×4-2
120 There are 6 digits in total. The numbers with 3 digits, with all digits distinct from each other, are the permutations of the 6 digits taken 3 at a time, and therefore there are 6*5*4 = 120 of them.
Since the order of the numbers (digits) does not matter in a combination, there is just 1.
012345 or -543210, if negative numbers are permitted.
Possible 5 digit combinations using 5 digits only 1 time is 5! or 5*4*3*2*1 or 120. Using 5 digits where numbers can be used 5 times is 55 or 3125.
10,000
45
6,000,054
5.55
99999
You can select 9 numbers for the first digit, 8 numbers for the second digit, and 7numbers for the third digit; so 504 (e.g. 9*8*7) different three digit numbers can be written using the digits 1 through 9.
5 and 55/100
0.355
0000 0001 0002 ... 9998 9999
depends on your answer
There are 60480 numbers.
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
There are 4^6 = 4096 such numbers.