>> in the 1st one i know how tocontinue but i just don't know how to make the programe take the values in ascending order

Given the problem description I don't think you need to: just input the numbers in increasing order, for example

Enter length 1: 5

Enter length 2: 7

Enter length 3: 9

But if you need to be able to handle non-increasing order, e.g.

Enter length 1: 9

Enter length 2: 5

Enter length 3: 7

you could swap them around with comparisons. A three-way swap is not difficult to figure out. If a>b then the largest is whichever is larger of a and c, and the smallest is whichever is the smaller of b and c. The middle value is the one that's left.

>> the second one i have solvet by using only printF

Great, well done! See, it's not that difficult when you start working on it, the trick is not to be overawed by the amount of work placed in front of you, just break it down and take it one step at a time.

>> and the 3rd i didn't know how to start cz i did not know how to make the program shoose 5 random questiond

Easiest way is to figure out how to make the program choose one random question, then to put that in a (for i=0; i<5; i++) loop. But the question itself tells you a lot:

- the program must initially promot the child the number of exercise he\she desires to do

I guess here "promot" means something like ask. So that means using cin or scanf as you've been shown. Store that value somewhere and use it in a loop's terminating expression.

- each exercise displays the questions in form a*b=? where a and b are single-gigits numbers (0-9) chosen randomly using the functions srand() and rand()

I don't know what a gigit is, digit perhaps? Anyway, do you know how to get a number from 0-9 using srand() and rand()? You're unlikely to be asked this without any background, so check through your course notes and you should find it with some examples, and you may even be lucky enough to have an example that shows how to get a single-digit random number. Do that twice and store the results into variables named a and b.

- for each answer the program displays "true" or "false"

OK so that means you need to get the answer from the user, and calculate the answer yourself, and compare the two results. You already know how to get input, and you should be able to figure out how to calculate the answer, so get both of those into separate variables and use the == operator, and display "true" or "false" accordingly.

- upon termination the program displays the test score.

This means you'll need some way of counting the number of correct answers. So you could think up a new variable name, initialise it to zero at the start of the program, then increment it each time you print "true".