You can use the following numeric functions in your fields' display text or in the values of your skip or validation logic.

Function | Description | Example |
---|---|---|

number(* arg) | Converts its argument to a number. | =number("42") returns 42 (which can then be used for numerical calculations) |

random() | Generates and returns a uniformly distributed random number in the range from 0.0 up to but excluding 1.0. | =int((random()*(10 - 2)) + 2) returns a random whole number between 2 and 10 |

int(number arg) | Converts the argument to an integer (a whole number) by discarding the fractional component. | =int(pi()) returns 3 |

max(value_1, value_2, ...*) | Returns the maximum value of the result of converting each argument to a number. | =max($age1, $age2, $age3) |

min(value_1, value_2, ...*) | Returns the minimum value of the result of converting each argument to a number. | =min($age1, $age2, $age3) |

round(number arg, number decimals?) | Returns the closest number to the given argument, with the specified number of decimal places (if any). | =round(pi(), 2) returns 3.14 |

pow(number value, number power) | Returns the result of raising the first argument to the power of the second. | see BMI calculation example below |

log(number arg) | Returns the natural logarithm of the argument. | |

log10(number arg) | Returns the base-ten logarithm of the argument. | |

abs(number arg) | Returns the absolute value of the argument (no sign). | |

sin(number arg) | Returns the sine of the argument, expressed in radians. | |

cos(number arg) | Returns the cosine of the argument, expressed in radians. | |

tan(number arg) | Returns the tangent of the argument, expressed in radians. | |

asin(number arg) | Returns the arc sine of the argument, the result being in the range -π/2 to +π/2 radians. | |

acos(number arg) | Returns the arc cosine of the argument, the result being in the range zero to +π radians. | |

atan(number arg) | Returns the arc tangent of the argument, the result being in the range -π/2 to +π/2 radians. | |

atan2(number arg) | Returns the angle in radians subtended at the origin by the point on a plane with coordinates (x, y) and the positive x-axis, the result being in the range -π to +π. | |

sqrt(number arg) | Returns the non-negative square root of the argument. | |

exp(number arg) | Returns the value of e^x. | |

exp10(number arg) | Returns the value of 10^x. | |

pi() | Returns an approximation to the mathematical constant π. |

**Tip****:** if your calculation does not seem to work correctly, try adding white space around the operator, e.g. instead of "=($field_1+5)" use "=($field_1 + 5)"

**Also see here for more functions and expressions you can use. **

**Example**

*The participant's BMI must be calculated by dividing the participant's weight (in kgs) by the participant's height (in meters squared). *

*Create a Number field to capture the participant's***weight**and set the Answer Format to be Decimal.

*Create a Number field to capture the participant's***height**and also set the Answer Format to be Decimal.

*Create an Information field to display the calculated BMI value.**Type the expression into the Information field display text as follows, using the pow() function to square the height value:*

*Wrap the expression in the round() function to round the result to two decimal places:*

*This will display on the device as:*