I notice that in the first few exercises teaching syntax, the last phrase within the parenthesis jumps from counter=++ to i=i+1. Now, i understand the substitution for counter with i, but why the change in the last phrase with no explanation? What does the change represent if anything at all?

# Basic Syntax on for statements

**mtf**#2

Basic `for`

statement

```
for (var i = 1; i < 21; i++) {
// loop code body
}
```

The statement takes three parameters:

```
1. iterator variable declaration and initialization => Start
2. conditional expression => End
3. increment/decrement expression => Step
```

Your question concerns #3, the Step. This can be any expression that modifies the iterator value, and it can be in either direction, up or down the number line.

We can start with a higher value, and work backwards through a set of numbers with a negative step.

```
// count down by 5's
for (var i = 50; i > 0; i -= 5) {
console.log(i);
}
```

Output

```
50
45
40
35
30
25
20
15
10
5
```

We use a shorthand arithmetic assignment operator above, `-=`

. The expression,

`i -= 5`

is the equivalent to,

`i = i - 5`

In both cases, `i`

has `5`

taken away.

This expression,

`i++`

is equivalent to,

`i = i + 1`

and this,

`i--`

is the same as,

`i = i - 1`

It is touched upon, but only briefly in the track. We do get plenty of practice though, so any confusion around this should clear up, presently. In the meantime, search for `JavaScript arithmetic operators`

and visit the MDN link that comes up in the SERP.

**lbarbul1**#3

Thank you. I should have waited a few more lessons when this explained itself. Thank you for the response.