Calculation Mental: Addition and Subtraction. What is the total amount of money Cristiane and Daniele spent together? How much did Cristiane spend ...

Calculation Mental: Addition and Subtraction. What is the total amount of money Cristiane and Daniele spent together? How much did Cristiane spend more than Daniele? Solve the following problems using mental calculation: Dona Eliana has a stand at the Jaçanã fair in São Paulo. She started the day with 70 watermelons to sell. She sold 22 watermelons in the morning and 17 in the afternoon. How many watermelons did Dona Eliana sell? Explain how you solved this calculation to a colleague. If Dona Eliana took 70 watermelons and sold 39, how many watermelons were left? Calculate mentally the following situations-problem and register the results. Choose one of the strategies below and solve the problems. Mariana went to the bakery and bought 22 breads for the afternoon coffee with her friends. When she got home, she saw that her mother had bought 25 breads. What is the total number of breads bought by them? A fisherman caught 43 sardines in the morning and 36 in the afternoon. How many sardines were caught? For a volleyball match, the visiting team brought 85 fans and the local team, 115 fans. How many fans watched the game?
Calculation Mental
Addition and Subtraction
The strategies of mental calculation are important to make the resolution of operations faster and easier.
To add or subtract quantities, it is possible to use decomposition, rounding, compensation for some term or parcel, and separation of orders.
Knowing the various mental calculation procedures allows choosing the most appropriate one for each presented problem situation.