Formula guides, error fixes and finance walkthroughs. Many come with a live sheet, so you check your own answer instead of only reading one.
Excel's NPV discounts the first number you give it. If that number is today's investment, your answer is wrong. Here's the fix, worked through, and a sheet that grades yours.
The green badge means there's a graded sheet inside.
#DIV/0! means a formula divided by zero or by an empty cell. Why it happens, averages of nothing included, and how to show a clean result, with a practice sheet.
Extra spaces, names in the wrong order, numbers stored as text and dates that aren't dates: the cleaning task interviewers love, solved with formulas, and a sheet that grades yours.
List each customer once, A to Z, for the region someone picks, in one formula that updates itself. The dynamic-array answer interviewers look for, and a sheet that grades yours.
The finance question in Excel interviews: a loan's monthly payment and its total interest, with the rate, period and sign traps explained, an NPV follow-up, and a sheet that grades yours.
The lookup task almost every Excel interview includes: bring a value across from a second table. The answer interviewers want, why VLOOKUP fails here, and a sheet that grades yours.
Turn a raw sales list into a summary by region and product, without a pivot table. The formula interviewers expect, the $ signs that make it copy, and a sheet that grades yours.
Invoices due at the end of next month, and the working days a client has to pay: the date task interviewers set, solved with EOMONTH and NETWORKDAYS, plus a sheet that grades yours.
#NAME? means Excel doesn't recognise a word in your formula: a misspelt function, text without quotes, a missing colon. Find it and fix it, with a practice sheet.
#NUM! means a calculation has no valid answer: an IRR with no rate to find, a square root of a negative. Each cause and its fix, with a practice sheet.
#REF! means a formula points at a cell that isn't there: deleted, or past the edge of a range. The usual causes and fixes, with a practice sheet.
#VALUE! means a formula got the wrong kind of value, most often text where it needs a number. The usual causes and fixes, with a practice sheet.
#N/A means a lookup didn't find what it was looking for. Here are the six usual causes, how to spot each one on the sheet, and the fix, with a practice sheet.
#SPILL! means a formula's result needs more cells than are free. Here's how to find what's in the way, the other causes of #SPILL!, and how to fix each one.
XLOOKUP does everything VLOOKUP does with fewer ways to go wrong. Here's the same lookup written both ways, the five differences that matter, and when VLOOKUP is still the right call.
Nothing matches yet. Try the function reference.
What each one means, and the fix that usually works.
Every function page has the syntax, worked examples on a real sheet and the mistakes people make.
Find a value in a table and bring back what sits next to it.
Make a formula decide: test a condition, catch an error.
Add and count, all of it or only the rows that match.
Build dates, move them by months or working days, and count the time between two.
Show numbers and dates as text, in exactly the format you want.
One formula that returns a whole list and spills it down the sheet.
Loans, present values and returns.
Practise in a live grid that grades what your formula calculates, with a specific hint when it's wrong.
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