You may also consider to read some of the fine tutorials and books to learn Nim :-)
For Nim we have the $ letter for universal "to string" conversion, which works
for most data types including int. So try
echo $(int1 + int2) # plain $int1 for single value
Run
Other functions with more formating options, for example leading zeros for ints
or decimal digits for float exists also, see std lib.
