1
Equal or unequal?
Discover Mathematics P2: Term 2, Lessons 101–110
GoalTell whether a whole has been cut into equal parts or unequal parts.
New words
whole · the complete shape or objectpart · one piece of a wholeequal parts · parts that are exactly the same sizeunequal parts · parts that are not the same size
Explanation
A whole can be cut into parts. If all the parts are exactly the same size, they are equal parts. If some parts are big and some are small, they are unequal parts. Fractions need equal parts. A round flatbread cut straight through the middle makes 2 equal parts. If you cut near the edge, one piece is big and one is small, so they are not equal.
Worked examples
A paper rectangle is cut in the middle. Both parts are the same size, so they are equal parts. There are 2 equal parts.
This rectangle is cut near one side. One part is much bigger than the other, so the parts are unequal.
Mina folds a square paper from corner to corner and cuts along the fold. She gets 2 triangles that fit exactly on each other, so they are equal parts.
Class activity
Fold and cut. Take a sheet of paper and fold it so that the two halves fit exactly on each other. Cut along the fold. Put one piece on top of the other: are they equal? Now cut another sheet along a line that is not in the middle and check again.
Practice
1
Are the parts equal?
Yes. The square is cut into 4 equal parts.
2
Are the parts equal?
No. The parts are different sizes.
3
A round flatbread is cut into 3 pieces. One piece is huge and two are tiny. Are the pieces equal parts?
No. Equal parts must be the same size.
4
Youssef shares a rectangular cake between 2 children. Where should he cut so each child gets an equal part?
Straight through the middle, so both pieces are the same size.
5
How many equal parts does the whole have?
4 equal parts.