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It depends on the nature of your work. Singapore, somewhat unusually, doesn't have tourist visas, only Short-Term Visit Passes (STVP). STVPs explicitly allow some work-like activities like "attending meetings" and have a longer list of activities permitted on notification, including "transfer of knowledge on process of new operations in Singapore". See the Ministry of Manpower for a full list.
You can legally conduct these "Work Pass Exempt activities" for up to 90 days in any year-long period, so your plan to visit multiple times is also OK.