Maths Help - How do I EXPLAIN that the answer is 2 for.... | ExpatWoman.com
 

Maths Help - How do I EXPLAIN that the answer is 2 for....

1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 16:42

14 ÷ ? = 7

without knowing the answer already? This is meant to be an introductory question for division.

Only way I could think of is to say
7 x 2 = 14
14 ÷ 7 = 2
14 ÷ 2 = 7

and the third one matchs, so it must be 2. It's not very satisfactory in my mind.....

648
Posts
EW GURU
Latest post on 17 October 2011 - 19:58
Yes we used the word backwards or opposite which she seems to get, "inverse" is too complicated.... [b'>9pq + 2q 2 [/b'>? Well done 2 stars LOL
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 18:14
Yes we used the word backwards or opposite which she seems to get, "inverse" is too complicated.... 9pq + 2q 2 ?
648
Posts
EW GURU
Latest post on 17 October 2011 - 18:04
In year 2 they are trying to get the children to understand that division is the opposite of multiplication and vice versa. Just explain to her that that the answer is the same when you work backwards by swapping the division for x . Wait until she’s 10, my son had this a few nights ago 3q(3p-q) + 5q 2 (the 2 at the end is to the power of 2) it took me an hour to work it out LOL
1100
Posts
EW OLDHAND
Latest post on 17 October 2011 - 17:08
14 ÷ ? = 7 without knowing the answer already? This is meant to be an introductory question for division. Only way I could think of is to say 7 x 2 = 14 14 ÷ 7 = 2 14 ÷ 2 = 7 and the third one matchs, so it must be 2. It's not very satisfactory in my mind..... If we have 14 biscuits how many groups would we need to have 7 biscuits in each group Thanks AS...OK....I think this one might work, not too many words to confuse. You can actually play around with the biscuits/apples/objects to give a visual. Then your LO will take out 7 biscuits since you said how many groups of 7 and then they'll count out another 7 and then you say so how many groups? then they say two! Then you say, well done, now what is two groups of seven equal to? and they say 14... yaay (i hate math)
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 17:08
Yr 2. Noo...she says she doesn't know what "inverse" is.
756
Posts
EW GURU
Latest post on 17 October 2011 - 17:05
What year is she in? At school they teach them the term "inverse" which is sort of opposite. So when they have a missing number they do the opposite to work it out. Like 14+ ? = 18 The opposite of + is - so she would do 18-14 to get the answer. Sorry very difficult to explain over a computer. 2 x ? = 8 inverse or reverse of the sum would be 8 divide 2 = 4. Not so sure this has been of great help to you. <em>edited by TimTam on 17/10/2011</em>
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 17:04
14 ÷ ? = 7 without knowing the answer already? This is meant to be an introductory question for division. Only way I could think of is to say 7 x 2 = 14 14 ÷ 7 = 2 14 ÷ 2 = 7 and the third one matchs, so it must be 2. It's not very satisfactory in my mind..... If we have 14 biscuits how many groups would we need to have 7 biscuits in each group Thanks AS...OK....I think this one might work, not too many words to confuse.
4329
Posts
EW MASTER
Latest post on 17 October 2011 - 17:03
Times tables! How many 7s are in 14? No need to explain - it is a fact - accept!
1100
Posts
EW OLDHAND
Latest post on 17 October 2011 - 17:02
14 ÷ ? = 7 without knowing the answer already? This is meant to be an introductory question for division. Only way I could think of is to say 7 x 2 = 14 14 ÷ 7 = 2 14 ÷ 2 = 7 and the third one matchs, so it must be 2. It's not very satisfactory in my mind..... If we have 14 biscuits how many groups would we need to have 7 biscuits in each group
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 17:00
Well, obviously you need the Algebraic commutative property of multiplication (and hence, division) in that 2 x 4 = 4 x 2 So if 14 / x = 7 its the same at 14 / 7 = x and x = 2 Yeah , I know that.....but it doesn't help!!!
1238
Posts
EW OLDHAND
Latest post on 17 October 2011 - 16:58
Well, obviously you need the Algebraic commutative property of multiplication (and hence, division) in that 2 x 4 = 4 x 2 So if 14 / x = 7 its the same at 14 / 7 = x and x = 2
348
Posts
EW EXPLORER
Latest post on 17 October 2011 - 16:57
you mean without using pens, apples or any object to empirically show what happens if you create groups of 7? I still have the same problem even if I use biscuits and I divide 14 biscuits by 7, I get 2 lots. It answers 14 ÷ 7 = ? , doesn't answer the question of 14 ÷ ? = 7......in my mind. edited by Sugarbeach on 17/10/2011 In a way it does, if you put it like this: i have 14 biscuits and I need to distribute them to some children in groups of seven for each child, but I do not know how many children will have the seven biscuits. So I start creating a group of seven. Then I create another group of seven. Oh, the 14 biscuits are over! So how many groups did I create? Two. So two children will have the seven. It might work if you do not eat the biscuits in the process. At least, I hope it will work!
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 16:55
OOH me head hurts just reading this thread :D Sorry Genie....I can say that my DD feels your pain :D
184
Posts
EW NEWBIE
Latest post on 17 October 2011 - 16:54
You need to show that there is 14 in a group. You need to Help them understand there are 7 in a group but how many groups are there total? Get them to circle 7 dots out of 14 total dots and they will see what the missing number is. The problem is the child needs to understand you're talking about total, numbers in a group and amount of groups. Good luck!
927
Posts
EW GURU
Latest post on 17 October 2011 - 16:51
OOH me head hurts just reading this thread :D
1566
Posts
EW EXPERT
Latest post on 17 October 2011 - 16:50
you mean without using pens, apples or any object to empirically show what happens if you create groups of 7? I still have the same problem even if I use biscuits and I divide 14 biscuits by 7, I get 2 lots. It answers 14 ÷ 7 = ? , doesn't answer the question of 14 ÷ ? = 7......in my mind. <em>edited by Sugarbeach on 17/10/2011</em>
5400
Posts
EW MASTER
Latest post on 17 October 2011 - 16:47
Using the Multiplication Tables? Oh, sorry, you did. Asking how many 7s you need to make 14? <em>edited by simpleasabc on 17/10/2011</em>
348
Posts
EW EXPLORER
Latest post on 17 October 2011 - 16:46
you mean without using pens, apples or any object to empirically show what happens if you create groups of 7?
 
 

ON EXPATWOMAN TODAY