Do you add up first 7 + 8 and then 2 + 4? Or do you round up to the tens and minus later?
Answer quickly: how much is 27 + 48?
Yes, the answer is 75. But what happened in your head when you knocked out the numbers?
There was a recent conversation on Facebook in which hundreds of thousands of people have told how to calculate the simple total themselves. There are a surprising number of different creative ways. Among other things, this is how the respondents came to the conclusion:
■ 20 + 40 = 60, then 7 + 8 = 15, finally 60 + 15 = 75.
■ Rounded to 27 30 and 48 50. 30 + 50 = 80, minus the rounded 3 + 2 = 5, and the result is 75.
■ Round to equal numbers, ie move from 27 to 2 and add it to 48, making the addition a little easier to handle 25 + 50.
■ Starting with Chapter 48, add ten and then another ten. The remaining 7 fingers are then added to the 68 using the aid.
■ Starting from Chapter 27, adding ten four times, keeping in mind the number 67, then adding the remaining 8 to Chapter 7. 8 + 8 = 16, from which one is taken and 15 is obtained, combined 60 + 15 = 75.
■ Some see the calculation visually as a traditional underlining. Then the right-hand ones 7 and 8 are first plucked, and one of the number 15 obtained is moved above the numbers on the left and the viton under the right-hand ones. Then we add 1 + 2 + 4 and get 7 in front of the vitos, ie 75.
Flexibility is the word of the day
There are many solutions, and that is what we would like to pay more attention to in the teaching of mathematics today, says a teacher of mathematics, a researcher Marika Toivola.
– Instead of teaching one right way, it would be important for the teacher to be interested in the way the child and the individual think. Mathematics cannot become meaningful unless one can look for meanings oneself, Toivola states.
– These are all right habits and should by no means be valued. Then it is good in mathematics if you can flexibly use different ways.
According to Toivola, it is possible to predict from an early age how they will do in mathematics during their school hours. When asked, one child can immediately tell how many buttons there are in his or her sweater. The other has never dropped the buttons on his shirt, but knows what they look like.
– This is not as small as you suddenly think. If a child draws or is directed to pay attention to numbers as a child, the prognosis for success in school mathematics is clearly better. This would seem to carry even more over the stage when mathematics around the 4th and 5th grades becomes more abstract. Children who have paid attention to numbers from an early age are seen in the school world as “mathematically gifted”.
Therefore, it would be important for children to be instructed to consider the amounts at an early stage, Toivola says. In addition, the discussion of different calculation methods is valuable. By comparing one’s own ways, flexibility is developed, which in turn benefits the development of mathematical thinking.
– Flexibility is the word of the day.
Source site www.is.fi