diff --git a/lesson11/l11 b/lesson11/l11
new file mode 100755
index 0000000..92f24d4
Binary files /dev/null and b/lesson11/l11 differ
diff --git a/lesson11/l11.asm b/lesson11/l11.asm
new file mode 100644
index 0000000..77ddf89
--- /dev/null
+++ b/lesson11/l11.asm
@@ -0,0 +1,18 @@
+
+; %include '../lib/fl.asm' ; local
+%include 'lib/fl.asm' ; build.sh
+
+SECTION	.text
+global	_start
+
+_start:
+mov	ecx, 0
+
+nextNumber:
+inc	ecx
+mov	eax, ecx
+call	iprintLF
+cmp	ecx, 10
+jne	nextNumber
+
+call	quit
diff --git a/lesson11/l11.o b/lesson11/l11.o
new file mode 100644
index 0000000..e4f12c6
Binary files /dev/null and b/lesson11/l11.o differ
diff --git a/lesson12/l12 b/lesson12/l12
new file mode 100755
index 0000000..32567ba
Binary files /dev/null and b/lesson12/l12 differ
diff --git a/lesson12/l12.asm b/lesson12/l12.asm
new file mode 100644
index 0000000..793136e
--- /dev/null
+++ b/lesson12/l12.asm
@@ -0,0 +1,15 @@
+
+; %include '../lib/fl.asm' ; local
+%include 'lib/fl.asm' ; build.sh
+
+SECTION .text
+global	_start
+
+_start:
+mov	eax, 90
+mov	ebx, 9
+add	eax, ebx
+call	iprintLF
+
+call	quit
+
diff --git a/lesson12/l12.o b/lesson12/l12.o
new file mode 100644
index 0000000..08b8c65
Binary files /dev/null and b/lesson12/l12.o differ
diff --git a/lesson13/l13 b/lesson13/l13
new file mode 100755
index 0000000..58f5673
Binary files /dev/null and b/lesson13/l13 differ
diff --git a/lesson13/l13.asm b/lesson13/l13.asm
new file mode 100644
index 0000000..6bf74a7
--- /dev/null
+++ b/lesson13/l13.asm
@@ -0,0 +1,15 @@
+
+; %include '../lib/fl.asm' ; local
+%include 'lib/fl.asm' ; build.sh
+
+SECTION .text
+global	_start
+
+_start:
+mov	eax, 90
+mov	ebx, 9
+sub	eax, ebx
+call	iprintLF
+
+call	quit
+
diff --git a/lesson13/l13.o b/lesson13/l13.o
new file mode 100644
index 0000000..1220bff
Binary files /dev/null and b/lesson13/l13.o differ
diff --git a/lesson14/l14 b/lesson14/l14
new file mode 100755
index 0000000..a081149
Binary files /dev/null and b/lesson14/l14 differ
diff --git a/lesson14/l14.asm b/lesson14/l14.asm
new file mode 100644
index 0000000..4dd305e
--- /dev/null
+++ b/lesson14/l14.asm
@@ -0,0 +1,15 @@
+
+; %include '../lib/fl.asm' ; local
+%include 'lib/fl.asm' ; build.sh
+
+SECTION .text
+global	_start
+
+_start:
+mov	eax, 90
+mov	ebx, 9
+mul	ebx
+call	iprintLF
+
+call	quit
+
diff --git a/lesson14/l14.o b/lesson14/l14.o
new file mode 100644
index 0000000..9030154
Binary files /dev/null and b/lesson14/l14.o differ
diff --git a/lesson15/l15 b/lesson15/l15
new file mode 100755
index 0000000..437902f
Binary files /dev/null and b/lesson15/l15 differ
diff --git a/lesson15/l15.asm b/lesson15/l15.asm
new file mode 100644
index 0000000..e4c3d09
--- /dev/null
+++ b/lesson15/l15.asm
@@ -0,0 +1,21 @@
+
+; %include '../lib/fl.asm' ; local
+%include 'lib/fl.asm' ; build.sh
+
+SECTION	.data
+msg1	db	' remainder '
+
+SECTION .text
+global	_start
+
+_start:
+mov	eax, 90
+mov	ebx, 9
+div	ebx
+call	iprint
+mov	eax, msg1
+call	sprint
+mov	eax, edx
+call	iprintLF
+
+call	quit
diff --git a/lesson15/l15.o b/lesson15/l15.o
new file mode 100644
index 0000000..31986df
Binary files /dev/null and b/lesson15/l15.o differ
diff --git a/lib/fl.asm b/lib/fl.asm
index cd1af23..a25a640 100644
--- a/lib/fl.asm
+++ b/lib/fl.asm
@@ -1,3 +1,56 @@
+;------------------------------------------
+; void iprint(Integer number)
+; Integer printing function (itoa)
+iprint:
+push	eax
+push	ecx
+push	edx
+push	esi
+mov	ecx, 0
+
+divideLoop:
+inc	ecx
+mov	edx, 0
+mov	esi, 10
+idiv	esi
+add	edx, 48
+push	edx
+cmp	eax, 0
+jnz	divideLoop
+
+printLoop:
+dec	ecx
+mov	eax, esp
+call	sprint
+pop	eax
+cmp	ecx, 0
+jnz	printLoop
+
+pop	esi
+pop	edx
+pop	ecx
+pop	eax
+ret
+
+
+
+;------------------------------------------
+; void iprintLF(Integer number)
+; Integer printing function with linefeed (itoa)
+iprintLF:
+call	iprint
+
+push	eax
+mov	eax, 0Ah
+push	eax
+mov	eax, esp
+call	sprint
+pop	eax
+pop	eax
+ret
+
+
+
 ;------------------------------------------
 ; int slen(String message)
 ; String length calculation function