What is the correct way to spell the number 40 in English?

The correct spelling of the number 40 in English is 'forty.' Despite four being spelled with 'u,' the 'u' is dropped in forty. Spelling numbers correctly is crucial in both academic and real-world situations involving financial, quantitative, and logistical information. Correct spelling ensures precision and clarity in communication, reducing misunderstandings and errors, especially in written transactions or documentation.