Today we solve 10 basic problems using PHP, it’s very easy to learn, also a trending language today.

**1. To Add Two Numbers**

We’re currently practicing performing basic addition operations with two integer numbers.

```
<?php
$firstNum = (int)readline('Enter an integer: ');
$secondNum = (int)readline('Enter an integer: ');
function sum($a,$b) {
$c = $a+$b;
echo $c;
}
sum($firstNum, $secondNum)
?>
# input 10 , 8
# output 18
```

**2. Convert Celsius To Fahrenheit**

We can implement the formula for converting Celsius to Fahrenheit in Python code by using the expression (0°C × 9/5) + 32 = 32°F.

```
<?php
$c_temp = (int)readline('Enter an integer: ');
$f_temp = (($c_temp*9)/5)+32;
echo "Fahrenheit: $f_temp";
?>
# input 36
# output 96.8
```

**3. Convert Kilometers To Miles** **in javascript**

We know 1 kilometer is approximately equal to 0.62 miles, we can easily calculate the distance in miles by multiplying the distance in kilometers by 0.62.

```
<?php
function kmToMiles($km) {
return $km*0.62;
}
$km = (int)readline('Enter Km: ');
echo "Miles: ".kmToMiles($km);
?>
# input 5
# output 3.1
```

**4. Is A Number Positive Or Negative**

We can easily determine whether a number is positive or negative using this logic: if the number is equal to or greater than zero, then it’s positive; otherwise, it’s negative.

```
<?php
function isPositive($num) {
$check = $num >=0 ? "positive" : "negetive";
return $check;
}
$num = (int)readline('Enter Number: ');
echo isPositive($num);
?>
# input 2
# output positive
# input -3
# output negetive
```

**5. Is A Number Even Or Odd**

We can determine whether a number is even or odd by dividing it by 2 and checking the remainder (modulus). If the remainder is zero, then the number is even; otherwise, it’s odd.

```
<?php
function evenOrOdd($num) {
if ($num != 0) {
$check = $num%2 == 0 ? "Even" : "Odd";
echo $check;
} else {
echo "not Even or Odd";
}
}
$num = (int)readline('Enter Number: ');
echo evenOrOdd($num);
?>
# input 2
# output even
# input 3
# output odd
```

**6. Find the Largest Number from a List**

Here, we’re leveraging PHP default function `max()`

. Later on, we’ll explore implementing custom methods using loops or recursion.

```
<?php
$numArray = [2,5,3,1,4];
echo "max number is " . max($numArray);
?>
# input [2,5,3,1,4]
# output 5
```

**7. Determine whether a year is a leap year or not**

We can determine whether a year is a leap year by the following rules: if the year is divisible by 400, it’s a leap year. If it’s not divisible by 400 but divisible by 4 and not divisible by 100, then it’s also a leap year; otherwise, it’s not leap year.

```
<?php
function isLeapYear($year) {
if ($year%400==0 or $year%4==0 and $year%100!=0) {
echo "leap year";
} else {
echo "not leap year";
}
}
$year = (int)readline('Enter the Year: ');
isLeapYear($year)
?>
# input 1996
# output leap year
# input 2300
# output not leap year
```

**8. Find The Factorial Of A Number**

The factorial of a non-negative integer 𝑛*n*, denoted by 𝑛!*n*!, is the product of all positive integers less than or equal to 𝑛*n*. For example:

𝑛!=𝑛×(𝑛−1)×(𝑛−2)×…×3×2×1*n*!=*n*×(*n*−1)×(*n*−2)×…×3×2×1

For instance, 5!=5×4×3×2×1=1205!=5×4×3×2×1=120.

```
<?php
function factorial($num) {
$output = 1;
while ($num>1) {
$output = $output * $num;
$num = $num - 1;
}
echo $output;
}
$num = (int)readline('Enter a number: ');
echo factorial($num)
?>
# input 5
# output 120
see same problems solutions in python
```

If you don’t understand the syntax properly, then learn from here