An infinite number of ways.
.1+.9, .2+.8, .3+.7, .4+.6
then, .01+.99, .02+.98, .03+.97, ....
then, .001+.999, .002+.998
Then there are multiples:
1*1, 2*.5, etc
And that is only using binary operations. You could have .1+.1+.8, .1+.2+.7 (ternary operations), as well
50
Infinitely many. Here are a few: 1+22.45 1*23.45 2345/100 25.45-2 cuberoot(12895.213625)
there are 5 ways
293 ways
7.5 can be written an infinite number of ways; e.g. 75/10; 750/100; 7500/1000 along with many other ways.
With whole numbers, there are five ways.
There are infinitely many ways to get to 100.
50
9x9+9+9+9/9
3
There are many. Various ways to make a dollar using coins. 100 pennies, 4 quarters, 2 50 cent coins, 1 50 cent coin and 2 quarters, 10 dimes, 20 nickels, and many variations. There are 293 ways to make a dollar but maybe there are more possible ways.
There are many ways to make the number 50 by combining different numbers through addition, subtraction, multiplication, and division. Some examples include 25+25, 100-50, 10*5, and 100/2. The total number of ways to make 50 depends on the range of numbers and operations allowed in the calculation.
there is none
100
9
There are over 100 ways to help the earth... : )
There are an infinite number of ways in which the number 100 can be obtained from mathematical operations.