diff --git a/src/api/app/controllers/webui/staging/workflows_controller.rb b/src/api/app/controllers/webui/staging/workflows_controller.rb
index 5b9648e190a..09fc97788c8 100644
--- a/src/api/app/controllers/webui/staging/workflows_controller.rb
+++ b/src/api/app/controllers/webui/staging/workflows_controller.rb
@@ -120,11 +120,11 @@ def project_weight(project)
              when :acceptable
                10_000
              when :review
-               20_000 - helpers.review_progress(project) * 10
+               20_000 - (helpers.review_progress(project) * 10)
              when :testing
-               30_000 - helpers.testing_progress(project) * 10
+               30_000 - (helpers.testing_progress(project) * 10)
              when :building
-               40_000 - helpers.build_progress(project) * 10
+               40_000 - (helpers.build_progress(project) * 10)
              when :failed
                50_000
              when :unacceptable
diff --git a/src/api/app/helpers/webui/staging/workflow_helper.rb b/src/api/app/helpers/webui/staging/workflow_helper.rb
index cce293980c6..187b578d90f 100644
--- a/src/api/app/helpers/webui/staging/workflow_helper.rb
+++ b/src/api/app/helpers/webui/staging/workflow_helper.rb
@@ -20,7 +20,7 @@ def review_progress(staging_project)
     total = Review.where(bs_request: staging_project.staged_requests).size
     missing = staging_project.missing_reviews.count { |missing_review| staged_requests_numbers.include?(missing_review[:request]) }
 
-    100 - missing * 100 / total
+    100 - (missing * 100 / total)
   end
 
   def testing_progress(staging_project)
@@ -29,7 +29,7 @@ def testing_progress(staging_project)
     not_done = staging_project.checks.pending.size + staging_project.missing_checks.size
     all_checks = staging_project.checks.size + staging_project.missing_checks.size
 
-    100 - not_done * 100 / all_checks
+    100 - (not_done * 100 / all_checks)
   end
 
   def progress(staging_project)
diff --git a/src/api/app/helpers/webui/webui_helper.rb b/src/api/app/helpers/webui/webui_helper.rb
index fbdadd55ad0..a07011ad546 100644
--- a/src/api/app/helpers/webui/webui_helper.rb
+++ b/src/api/app/helpers/webui/webui_helper.rb
@@ -137,10 +137,10 @@ def elide(text, length = 20, mode = :middle)
       when :left # shorten at the beginning
         shortened_text = '...' + text[text.length - length + 3..text.length]
       when :middle # shorten in the middle
-        pre = text[0..length / 2 - 2]
+        pre = text[0..(length / 2) - 2]
         offset = 2 # depends if (shortened) length is even or odd
         offset = 1 if length.odd?
-        post = text[text.length - length / 2 + offset..text.length]
+        post = text[text.length - (length / 2) + offset..text.length]
         shortened_text = pre + '...' + post
       when :right # shorten at the end
         shortened_text = text[0..length - 4] + '...'
diff --git a/src/api/app/jobs/status_history_rescaler_job.rb b/src/api/app/jobs/status_history_rescaler_job.rb
index 111390e29e4..4bc43db5c6f 100644
--- a/src/api/app/jobs/status_history_rescaler_job.rb
+++ b/src/api/app/jobs/status_history_rescaler_job.rb
@@ -4,7 +4,7 @@ class StatusHistoryRescalerJob < ApplicationJob
   # this is called from a delayed job triggered by clockwork
   def perform
     maxtime = StatusHistory.maximum(:time)
-    StatusHistory.where('time < ?', maxtime - 365 * 24 * 3600).delete_all if maxtime
+    StatusHistory.where('time < ?', maxtime - (365 * 24 * 3600)).delete_all if maxtime
 
     keys = StatusHistory.distinct.pluck(:key)
     keys.each do |key|
@@ -47,7 +47,7 @@ def cleanup(key, offset, maxtimeoffset)
       items = find_start_items(allitems, curmintime + offset)
 
       if items.length > 1
-        timeavg = curmintime + offset / 2
+        timeavg = curmintime + (offset / 2)
         valuavg = (items.inject(0) { |sum, item| sum + item.value }).to_f / items.length
         Rails.logger.debug { "scaling #{key} #{curmintime} #{items.length} #{Time.at(timeavg)} #{valuavg}" }
         StatusHistory.delete(items.map(&:id))
diff --git a/src/api/app/models/branch_package.rb b/src/api/app/models/branch_package.rb
index 49fedbb10eb..b9d4be25173 100644
--- a/src/api/app/models/branch_package.rb
+++ b/src/api/app/models/branch_package.rb
@@ -136,7 +136,7 @@ def create_branch_packages(tprj)
         else
           tpkg = tprj.packages.new(name: pack_name)
         end
-        tpkg.bcntsynctag << '.' + p[:link_target_project].name.tr(':', '_') if tpkg.bcntsynctag && @extend_names
+        tpkg.bcntsynctag << ('.' + p[:link_target_project].name.tr(':', '_')) if tpkg.bcntsynctag && @extend_names
         tpkg.releasename = p[:release_name]
       end
       tpkg.store
diff --git a/src/api/app/models/bs_request.rb b/src/api/app/models/bs_request.rb
index 4cad759f6db..5cf1a534ef8 100644
--- a/src/api/app/models/bs_request.rb
+++ b/src/api/app/models/bs_request.rb
@@ -1137,8 +1137,8 @@ def raisepriority(new_priority)
   # This method checks makes sure this is the case.
   def change_priorities?(new_priority)
     new_priority == 'critical' ||
-      new_priority == 'important' && priority.in?(['moderate', 'low']) ||
-      new_priority == 'moderate' && priority == 'low'
+      (new_priority == 'important' && priority.in?(['moderate', 'low'])) ||
+      (new_priority == 'moderate' && priority == 'low')
   end
 
   def check_bs_request_actions!(opts = {})
diff --git a/src/api/app/models/event/build_fail.rb b/src/api/app/models/event/build_fail.rb
index 0badeb33a69..a94d9cba609 100644
--- a/src/api/app/models/event/build_fail.rb
+++ b/src/api/app/models/event/build_fail.rb
@@ -33,7 +33,7 @@ def state
 
     def faillog
       size = get_size_of_log(payload['project'], payload['package'], payload['repository'], payload['arch'])
-      offset = size - 18 * 1024
+      offset = size - (18 * 1024)
       offset = 0 if offset.negative?
       log = raw_log_chunk(payload['project'], payload['package'], payload['repository'], payload['arch'], offset, size)
       log.encode!(invalid: :replace, undef: :replace, universal_newline: true)
diff --git a/src/api/app/models/package.rb b/src/api/app/models/package.rb
index f15ac598911..1c37917dbf7 100644
--- a/src/api/app/models/package.rb
+++ b/src/api/app/models/package.rb
@@ -803,7 +803,7 @@ def self.activity_algorithm
   end
 
   def activity
-    activity_index * 2.3276**((updated_at_was.to_f - Time.now.to_f) / 10_000_000)
+    activity_index * (2.3276**((updated_at_was.to_f - Time.now.to_f) / 10_000_000))
   end
 
   def open_requests_with_package_as_source_or_target
diff --git a/src/api/app/models/project.rb b/src/api/app/models/project.rb
index 001f84f4b9f..0ab35f35408 100644
--- a/src/api/app/models/project.rb
+++ b/src/api/app/models/project.rb
@@ -217,9 +217,9 @@ def check_access?(project)
         # check if User.session! belongs to group.
         User.session!.is_in_group?(grouprel.group) ||
           # FIXME: please do not do special things here for ldap. please cover this in a generic group model.
-          CONFIG['ldap_mode'] == :on &&
+          (CONFIG['ldap_mode'] == :on &&
             CONFIG['ldap_group_support'] == :on &&
-            UserLdapStrategy.user_in_group_ldap?(User.session!, grouprel.group_id)
+            UserLdapStrategy.user_in_group_ldap?(User.session!, grouprel.group_id))
       end
     end
 
diff --git a/src/api/app/models/status_history.rb b/src/api/app/models/status_history.rb
index fa3051887ba..3370ba18dca 100644
--- a/src/api/app/models/status_history.rb
+++ b/src/api/app/models/status_history.rb
@@ -1,6 +1,6 @@
 class StatusHistory < ApplicationRecord
   def self.history_by_key_and_hours(key, hours = 24)
-    starttime = Time.now.to_i - hours.to_i * 3600
+    starttime = Time.now.to_i - (hours.to_i * 3600)
 
     where("time >= ? AND \`key\` = ?", starttime, key)
       .pluck(:time, :value)
diff --git a/src/api/app/views/webui/package/show.html.haml b/src/api/app/views/webui/package/show.html.haml
index f745e96363c..54abbe6aaaa 100644
--- a/src/api/app/views/webui/package/show.html.haml
+++ b/src/api/app/views/webui/package/show.html.haml
@@ -40,7 +40,7 @@
         Source Files
         - if @linkinfo && @revision_parameter.nil?
           %small
-            - if @expand && @expand.to_s == '1' || @forced_unexpand.present?
+            - if (@expand && @expand.to_s == '1') || @forced_unexpand.present?
               = link_to('(show unmerged sources)', package_show_path(project: @project.name, package: @package.name,
                                                                      rev: @revision_parameter, expand: '0'))
             - else
diff --git a/src/api/app/views/webui/user/_activity.html.haml b/src/api/app/views/webui/user/_activity.html.haml
index 147897153c0..2d961b88cd7 100644
--- a/src/api/app/views/webui/user/_activity.html.haml
+++ b/src/api/app/views/webui/user/_activity.html.haml
@@ -11,7 +11,7 @@
         %tr
           %td.week-day= Date::ABBR_DAYNAMES[(week_day + 1) % 7]
           - 53.times do |week_number|
-            - current_day = first_day + week_number * 7 + week_day
+            - current_day = first_day + (week_number * 7) + week_day
 
             - if current_day > last_day
               %td
diff --git a/src/api/lib/xpath_engine.rb b/src/api/lib/xpath_engine.rb
index 599242edb30..31b1f61c303 100644
--- a/src/api/lib/xpath_engine.rb
+++ b/src/api/lib/xpath_engine.rb
@@ -430,7 +430,7 @@ def evaluate_expr(expr, root, escape = false)
       when :attribute
         expr.shift # :qname token
         expr.shift # namespace
-        a << '@' + expr.shift
+        a << ('@' + expr.shift)
       when :literal
         value = (escape ? escape_for_like(expr.shift) : expr.shift)
         return '' if @last_key && @attribs[table][@last_key][:empty]
diff --git a/src/api/spec/helpers/webui/package_helper_spec.rb b/src/api/spec/helpers/webui/package_helper_spec.rb
index 31e54013222..f2940c20057 100644
--- a/src/api/spec/helpers/webui/package_helper_spec.rb
+++ b/src/api/spec/helpers/webui/package_helper_spec.rb
@@ -56,7 +56,7 @@
     end
 
     it 'breaks up long strings' do
-      long_string = 'a' * 50 + 'b' * 50 + 'c' * 10
+      long_string = ('a' * 50) + ('b' * 50) + ('c' * 10)
       sanitized_string = nbsp(long_string)
       expect(long_string.scan(/.{1,50}/).join('<wbr>')).to eq(sanitized_string)
     end
diff --git a/src/api/spec/models/kiwi/repository_spec.rb b/src/api/spec/models/kiwi/repository_spec.rb
index 2c6b6b55c37..7fd86d0efdc 100644
--- a/src/api/spec/models/kiwi/repository_spec.rb
+++ b/src/api/spec/models/kiwi/repository_spec.rb
@@ -56,11 +56,11 @@
         property_of do
           project = []
           range(1, 3).times do
-            project << string(/[a-zA-Z1-9]/) + sized(range(0, 20)) { string(/[-+\w.]/) }
+            project << (string(/[a-zA-Z1-9]/) + sized(range(0, 20)) { string(/[-+\w.]/) })
           end
           repository = []
           range(1, 3).times do
-            repository << string(/[a-zA-Z1-9]/) + sized(range(0, 20)) { string(/[-+\w.]/) }
+            repository << (string(/[a-zA-Z1-9]/) + sized(range(0, 20)) { string(/[-+\w.]/) })
           end
           path = "obs://#{project.join(':')}/#{repository.join(':')}"
           path
diff --git a/src/api/test/unit/status_helper_test.rb b/src/api/test/unit/status_helper_test.rb
index 01d7b03de0e..f767473a304 100644
--- a/src/api/test/unit/status_helper_test.rb
+++ b/src/api/test/unit/status_helper_test.rb
@@ -8,7 +8,7 @@ class StatusHelperTest < ActiveSupport::TestCase
     now = 10_000
     testarray = []
     10.times do |i|
-      testarray << [now - i * 10, i]
+      testarray << [now - (i * 10), i]
     end
     # [[10000, 0], [9990, 1], [9980, 2], [9970, 3], [9960, 4], [9950, 5], [9940, 6], [9930, 7], [9920, 8], [9910, 9]]
     # while the testarray increases, the timestamps go down, so the result needs to decrease