Ok so if i set a=1. Then a <3 so a*2 = 1*2 = 2. If i repeat this process 10 times , what do i have to do with the a value each time. Add them up ? 2 *10= 20 which is option c) which is wrong. The correct answer is e) 15.
There is no instruction
set a to 1, the instruction inside the loop is change a by 1. What is the value of a the first time it reaches this instruction?I thought "change a by 1" meant replace the value of 5 by 1.
You are not the first person to have been caught out by that, it's a confusing "feature" of Scratch.
Yes.
So we add 1 ? It becomes 6 and 6 is not smaller then 3 so we go back and keep adding 1 ? Repeating this 10 times gives a=15 which is correct.
No, as already mentioned. There's a difference between "set" and "change by". "Set" replaces the old value of the variable by some new value. "Change by" adds or subtracts some value to a variable. In the program "change a by 1" adds 1 each time in the loop. If it had said "change a by -2" it would have subtracted 2 each time in the loop.
In the program, a's value is always >= 5, so the if condition is never executed. Essentially what the code does is to increase a (which starts off at 5) by 1 ten times, which results in a's final value being 15.