107
Capacity: comparing and problems
Textbook Part 3, pp. 68–69
GoalUnderstand that only quantities of the same kind can be compared; recipe problems.
New words
quantity · kattalikof the same kind · bir turdagirecipe · retsept
Explanation
We cannot compare 5 l with 5 kg — one is capacity and the other mass. We compare only quantities of the same kind: litres with litres, kilograms with kilograms, centimetres with centimetres.
Worked examples
Juice: 3 l apple + 2 l pear = 5 l.
5 l + 11 l = 16 l; 16 l > 15 l.
Class activity
“Can we compare?”: pairs on the board (3 l and 5 l; 2 kg and 4 cm; 6 dm and 60 cm). Children tick the pairs that can be compared.
Practice
1
5 l + 11 l = ?
16 l
2
Can we compare 7 kg and 7 l?
No, they are different kinds
3
Put the sign: 25 l ... 52 l
<
4
Recipe: 4 l water, 2 l juice, 1 l syrup. How much drink?
7 l