Mathematics defines division as breaking into parts a larger unit to make several smaller units.
Division of 21 feet wallpaper into 3 feet section will give 7 small parts of the wallpaper.
To reach above answer, following calculation was made:
[tex]\begin{aligned} \rm Total\: length\:of \: the \:wallpaper &= 21\rm \:centimetres\\Length \:of\:each\:section &= 3\: \rm centimetres\end[/tex]
Therefore, number of sections will be the division of total length to length of each section.
[tex]\rm \begin{aligned} Number \:of \:sections &= \dfrac{\rmTotal\: length}{\rmLength\:of\:each\:section}\\ \\&= \dfrac{\rm 21\:centimetres}{\rm 3\:centimetres}\\\\&= \rm 7 \:sections \end[/tex]
Hence, 21 centimetres long wallpaper can be divided into 7 sections that are 3 centimetres long.
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