Excel handles dates and time using a scheme in which dates are serial numbers and times are fractional values. For example, June 1, 2000 12:00 PM is represented in Excel as the number 36678.5, where 36678 is the date...

To get the max of every nth column, you can use an array formula based on the MAX, MOD, and COLUMN functions. In the example shown, the formula in M5 is:
=MAX(IF(MOD(COLUMN(B5:K5)-COLUMN(B5)+1,L5)=0,B5:K5))
Note:...

To convert a time from one time zone to another, you can use a formula that converts hours entered as whole numbers to the decimal values that Excel recognizes as times. In the example shown, the formula in F5 is:
=...

To calculate work hours, taking into account break time that needs to be subtracted, you can use a formula based on the MOD function. MOD is used to handle start and end times that cross midnight. In the example shown,...

To sum every nth column, you can use a formula based on the SUMPRODUCT, MOD, and COLUMN functions.
In the example shown, the formula in L5 is:
=SUMPRODUCT(--(MOD(COLUMN(B5:J5)-COLUMN(B5)+1,K5)=0),B5:J5)
How this...

If you want to find the most recent Wednesday, or Saturday, or Monday, given a specific start date, you can use a formula that uses the MOD function.
How the formula works
Formulas that use the concept of "day of week...

To get the duration between two times in as decimal hour (i.e. 3 hrs, 4.5 hrs, 8 hrs, etc.) you can use a formula based on the MOD function.
In the example shown, the formula in D5 is:
=MOD(B2-A2,1)*24
Excel hours...

To add an ordinal suffix to a number (i.e. 1st, 2nd, 3rd, etc.) you can use a formula based on the CHOOSE function to assign the suffix.
In the example shown, the formula in C5 is:
=CHOOSE(B5,"st","nd...

To get the number at a specific place value you can use a formula based on the MOD function. By place value, we mean hundred thousands, ten thousands, thousands, hundreds, tens, ones, etc.
In the example shown, the...

To count cells that contain only odd numbers, you can use a formula based on the SUMPRODUCT function together with the MOD function.
In the example, the formula in cell E6 is:
=SUMPRODUCT(--(MOD(rng,2)=1))
This...

To generate a fixed value every N columns (for example, a fixed expense every 3 months, a fixed payment every 6 months, etc.) you can use a formula based on the MOD function.
In the example shown, generate a value of...

If you want to highlight every other row in a table (sometimes called zebra striping) with conditional formatting you can do so with a simple formula that uses either the ISEVEN or ISODD function. For example, if you...

To add a given number of minutes to a time, you can add minutes divided by 1440, or use the TIME function.
In the example shown, the formula in D5 is:
=B5+(C5/1440)
Note: make sure results are formatted as time....

To repeat a fixed value every 3 months, you can use a formula based on the DATEDIF and MOD functions. In the example shown, the formula in C4, copied down, is:
=IF(B4>=start,(MOD(DATEDIF(start,B4,"m")+n,n...

To highlight numbers that are multiples of a another number with conditional formatting, you can use a simple formula based on the MOD function.
In the example shown, the formula used to highlight multiples of 9 is...