https://support.google.com/docs/answer/3093208
COUPNUM - Google Docs Editors Help
Calculates the number of coupons, or interest payments, between the settlement date and the maturity date of the investment. Sample Usage...
google docscoupnumeditorshelp
https://www.feishu.cn/hc/en-US/articles/520539409055-coupnum-function-for-sheets
COUPNUM function for Sheets
I. Intro The COUPNUM function returns the number of coupon or interest payments between the settlement date and maturity date of a loan or investment.
coupnumfunctionsheets
https://support.microsoft.com/lv-lv/office/coupnum-funkcija-coupnum-a90af57b-de53-4969-9c99-dd6139db2522
COUPNUM (funkcija COUPNUM) - Microsoft atbalsts
coupnumfunkcijamicrosoftatbalsts