Developing numeracy intervention for primary schools: Approach, methodology and an experimental framework

structured-event.vrtx, line 134, column 18: freemarker.core._TemplateModelException: ?substring(...) argument #2 had invalid value: The index mustn't be greater than the length of the string, 13, but it was 16. ---- FTL stack trace ("~" means nesting-related): - Failed at: #local isostarthour = startiso8601?su... [in template "lib/view-utils.ftl" in macro "displayTimeAndPlace" at line 110, column 5] - Reached through: @viewutils.displayTimeAndPlace resour... [in template "layouts/time-and-place.ftl" at line 23, column 11] ----