Lesson Plan index

Mathematics: Algebra
Milk Crates

Key Stage 3: age 13 - 14

Links to the National Curriculum and Numeracy Strategy

  • Represent problems and solutions in algebraic or graphical forms.
  • Describe the general term of a simple sequence in words, then using symbols.

Duration
One-two hours

Learning Objectives

Pupils will:

  • select appropriate stategies to use for a numerical and algebraic problem.
  • represent problems and solutions in algebraic form.
  • find and describe in symbols the next term or nth term of a sequence where the rule is quadratic.

Resources required
Squared paper.

Learning activity
George works for a dairy that uses square milk crates. These can be divided up to contain a square number of bottles fitting the crates with dividers. Using two dividers George can fit four bottles into a crate. Using four dividers he can fit 9 bottles into another sized crate. See the diagram.

How many bottles can be fitted into a square crate if 30 dividers are used?
How many dividers would be needed for a square crate that could hold 100 milk bottles?

Start with the simple examples.

Crate
Number of dividers
d
Number of milk bottles
m
1
2
4
2
4
9
3
6
16

The pupils might notice the following.
Square numbers are involved and because the dividers are used in pairs then the number of them is always a multiple of two.
On each side of the crate there is one more spaces then the number of dividers.

A general rule for the number of milk bottles can be generated:m = (½d + 1)²

Extension
Investigate rectangular milk crates.