103
Solving measurement problems
Textbook Part 3, pp. 60–61
GoalSolve problems with units of length; draw shapes to given measurements.
New words
side · tomontriangle · uchburchaksquare · kvadrat
Explanation
We add and subtract lengths like ordinary numbers, but we must not forget to write the unit: 15 cm + 14 cm = 29 cm. The sum of all sides of a shape is the distance all the way round it.
Worked examples
A square with 3 cm sides: 3 + 3 + 3 + 3 = 12 cm.
49 school rooms need painting; 15 were done on day one and 14 on day two: 49 − (15 + 14) = 20 left.
Class activity
Draw a house in the notebook: the wall is a 6 cm square, the roof a triangle with 6 cm sides, the window a 3 cm square.
Practice
1
A triangle has sides 2 cm, 3 cm and 4 cm. Their sum?
9 cm
2
3 dm 4 cm = ? cm
34 cm
3
49 − (15 + 14) = ?
20
4
Write first the even, then the odd numbers in increasing order: 7, 2, 9, 4, 1, 8
2, 4, 8, 1, 7, 9