diff --git a/.travis.yml b/.travis.yml
index ec9d8e4..951ff42 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,10 +4,8 @@ os:
   - linux
   - osx
 julia:
-  - 1.0
-  - 1.1
-  - 1.2
   - 1.3
+  - 1.4
   - nightly
 notifications:
   email: true
@@ -16,8 +14,4 @@ matrix:
   allow_failures:
     - julia: nightly
 
-## uncomment the following lines to override the default test
-# script:
-  # - julia -e 'Pkg.clone(pwd()); Pkg.build("Groups"); Pkg.test("Groups"; coverage=true)'
-
 codecov: true
diff --git a/src/arithmetic.jl b/src/arithmetic.jl
index 933c5ec..c7e8c21 100644
--- a/src/arithmetic.jl
+++ b/src/arithmetic.jl
@@ -10,30 +10,29 @@ end
 #   Binary operators
 #
 
-function Base.append!(w::GWord{T}, v::AbstractVector{T}) where T
-    append!(syllables(w), v)
+function Base.push!(w::GWord{T}, s::T) where T <: GSymbol
+    push!(syllables(w), s)
     return w
 end
 
-function Base.prepend!(w::GWord{T}, v::AbstractVector{T}) where T
-    prepend!(syllables(w), v)
+function Base.pushfirst!(w::GWord{T}, s::T) where T <: GSymbol
+    pushfirst!(syllables(w), s)
     return w
 end
 
-Base.append!(w::T, v::T) where T <: GWord = append!(w, syllables(v))
-Base.prepend!(w::T, v::T) where T <: GWord = prepend!(w, syllables(v))
-
-for (mul, f) in ((:rmul!, :push!), (:lmul!, :pushfirst!))
-    @eval begin
-        function $mul(out::T, w::T, s::GSymbol) where T <:GWord
-            resize!(syllables(out), syllablelength(w))
-            syllables(out) .= syllables(w)
-            $f(syllables(out), s)
-            return freereduce!(out)
-        end
-    end
+function Base.append!(w::T, v::T) where T <: GWord
+    append!(syllables(w), syllables(v))
+    return w
 end
 
+function Base.prepend!(w::T, v::T) where T <: GWord
+    prepend!(syllables(w), syllables(v))
+    return w
+end
+
+Base.append!(w::T, v::T, others::Vararg{T,N}) where {N,T <: GWord} =
+    append!(append!(w, v), others...)
+
 function rmul!(out::T, x::T, y::T) where T<: GWord
     if out === x
         out = deepcopy(out)
@@ -51,15 +50,16 @@ function rmul!(out::T, x::T, y::T) where T<: GWord
     end
 end
 
+rmul!(out::T, v::T) where T<:GWord = freereduce!(append!(out, v))
+lmul!(out::T, v::T) where T<:GWord = freereduce!(prepend!(out, v))
+
 lmul!(out::T, x::T, y::T) where T <: GWord = rmul!(out, y, x)
 
-function AbstractAlgebra.mul!(out::T, x::T, y::T) where T <: GWord
-    return rmul!(out, x, y)
-end
+AbstractAlgebra.mul!(out::T, x::T, y::T) where T <: GWord = rmul!(out, x, y)
 
 (*)(W::GW, Z::GW) where GW <: GWord = rmul!(deepcopy(W), W, Z)
-(*)(W::GWord, s::GSymbol) = rmul!(deepcopy(W), W, s)
-(*)(s::GSymbol, W::GWord) = lmul!(deepcopy(W), W, s)
+(*)(W::GWord, s::GSymbol) = freereduce!(push!(deepcopy(W), s))
+(*)(s::GSymbol, W::GWord) = freereduce!(pushfirst!(deepcopy(W), s))
 
 function power_by_squaring(W::GWord, p::Integer)
     if p < 0
diff --git a/test/AutGroup-tests.jl b/test/AutGroup-tests.jl
index 7b29949..17fefcf 100644
--- a/test/AutGroup-tests.jl
+++ b/test/AutGroup-tests.jl
@@ -139,7 +139,7 @@
    @testset "reductions/arithmetic" begin
       f = Groups.AutSymbol(perm"(1,2,3,4)")
 
-      f² = append!(A(f), [f])
+      f² = push!(A(f), f)
       @test Groups.simplifyperms!(Bool, f²) == false
       @test f²^2 == one(A)
       @test !isone(f²)
diff --git a/test/FreeGroup-tests.jl b/test/FreeGroup-tests.jl
index da39e75..bf7520a 100644
--- a/test/FreeGroup-tests.jl
+++ b/test/FreeGroup-tests.jl
@@ -60,13 +60,28 @@ end
 
       t_symb = Groups.FreeSymbol(:t)
       tt = deepcopy(t)
-      @test string(Groups.rmul!(tt, tt, inv(t_symb))) == "(id)"
+      @test string(Groups.rmul!(tt, tt, inv(tt))) == "(id)"
       tt = deepcopy(t)
-      @test string(append!(tt, [inv(t_symb)])) == "t*t^-1"
+      @test string(Groups.lmul!(tt, tt, inv(tt))) == "(id)"
+
       tt = deepcopy(t)
-      @test string(Groups.lmul!(tt, tt, inv(t_symb))) == "(id)"
+      push!(tt, inv(t_symb))
+      @test string(tt) == "t*t^-1"
       tt = deepcopy(t)
-      @test string(prepend!(tt, [inv(t_symb)])) == "t^-1*t"
+      pushfirst!(tt, inv(t_symb))
+      @test string(tt) == "t^-1*t"
+
+      tt = deepcopy(t)
+      append!(tt, inv(t))
+      @test string(tt) == "t*t^-1"
+
+      tt = deepcopy(t)
+      prepend!(tt, inv(t))
+      @test string(tt) == "t^-1*t"
+
+      tt = deepcopy(t)
+      append!(tt, s, inv(t))
+      @test string(tt) == "t*s*t^-1"
    end
 
    @testset "reductions" begin