Let me think asks for a moment before answering. Let me think, it was either Tuesday or Wednesday.
It is honest rather than evasive, and it buys a pause without promising anything. Said slowly it also warns that the answer may not be the one wanted.
1phraselet me thinkAsking for a moment before answering.
“Let me think, I may have the number somewhere.”
let me think is a phrase.
Practised in Small Talk & Everyday Phrases