Hi Eric,
Greetings from Syncfusion support.
Based on your query we suspect that you want to an add number in a cell but it is shown as [object object]. If column’s type is not set then mentioned issue will occur. So, please set column’s type in columns definition.
Refer the help documentation.
If we misunderstood your query then please get back to us.
Regards,
Thavasianand S.