3. Do the food sums. 1 carrot = 50g, 1 lemon = 100g, 1 mango = 200g. 1) lemon + mango = lemon + mango. 2) carrot + lemon and mango = carrot + lemon + mango. 3) carrot + lemon + mango and carrot = two carrots + lemon + mango. 4) carrot + lemon + mango and two carrots + lemon + mango = three carrots + two lemons + two mangoes.

1) \(100 + 200 = 300\) g.

2) \(50 + (100 + 200) = 350\) g.

3) \((50 + 100 + 200) + 50 = 400\) g.

4) \((50 + 100 + 200) + (2 \cdot 50 + 100 + 200) = 350 + 400 = 750\) g.

Ответ: 1) 100 г + 200 г = 300 г; 2) 50 г + 300 г = 350 г; 3) 350 г + 50 г = 400 г; 4) 350 г + 400 г = 750 г.