Number Line
Study number relation through representation on the number line
x-axis as a number line
compare a+k and b+k
compare a and ka; familiarize with multiplication of directed numbers
compare ka and kb
solve an inequality

Some tasks about number line, adapted from junior math contests for primary 6 or secondary 1 students.
TM 06 question 14: number line
TM 06 question 15: number line