Can anyone please explain the following: (my son's homework KS2 Yr 5)
86 divided by 5 =
- 50 (10x5)
--
36
- 25 (5x5)
--
11
- 10 (2x5)
--
1 = 17 r1
Please help, its driving me bananas!
Problem 1Originally Posted by nogoodatmaths
Divide 86 by 5:
First see how many times 5 goes into 8 that is one thus the answer starts off as:
86 divided by 5 = 1,
then multiply the divisor which is 5 by the number you got which is 1,
86
5
Now subtract,
36.
Thus the answer thus far looks like,
86 divided by 5= 1
36
What you do is is divide 36 by 5, since 5 does not go into 3 move to the next digit, thus how many times 5 goes into 36 answer 7, thus
86 divided by 5=17
36
Now mutiply as in the beginning by 7 the divisor and subtract thus
36
-35
=1, since 5 cannot further go into 1 the remaining (remainder is 1) thus,
86 divided by 5= 17 R1
Umm, new Math, eh?Originally Posted by nogoodatmaths
By-product of sets, eh?
When we were young, Math was easy. No sets yet. When I reached high school, the head of sets came under the radar. In college, my nephews and nieces bugged me with their homeworks full of sets. Like your son's now. Those Pure Mathematicians should be crucified! Look what they'd done to Math.
Dividing 86 by 5 then was easy. You could tie my left hand to my back then and I could still get the answer easily. [The free right hand was for writing. or dividing on paper or sand.] No too much thinking. Now, kids, other than busloads of books per kid, they are to suffer simple divisions. Sigh.
Let us see,...
86 divided by 5.
The first step was to find how many tens of fives, or fives of tens, [heck], in 86. There are five of tens, or 50. ---- [5*10 = 50].
50 was subtracted from 86, and 36 remained.
Second step was to find how many fives of fives in that 36.
There are 5 of 5, or 25. ---[5*5 = 25].
25 was subtracted from the 36, and 11 remained
Tird step was to find anymore fives left in that 11.
There are two more fives, or 10. ------[5*2 = 10].
10 was subtracted from the 11, and 1 remained.
No more fives in that remaining 1.
So, how many fives they were in the original 86?
10 of fives, 5 of fives, 2 of fives. Those are 17 of fives.
Therefore, 86 divided by 5, or, 86 divided into 5's, is 17, remainder 1.
That is 17 fives, with a remainder of 1.
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That is how I'd interpret the solution you posted.
Which baffles me.
If kids are forced into sets now, [in preparation to modern Math (sets!) in college], why not the division of 86 into fives like this instead?:
How many tens are in 86? Eight. 8*10 = 80
How may fives are in a ten? Two. So, in 8 of tens there must be 16 of 5's.
Subtract 80 from 86. Six remains.
How many fives in 6? One. And there remains a 1, or digit 1.
So, 16 +1 = 17 fives, plus a remainder of 1.
Therefore, 86 divided by 5 = 17, remainder 1.
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I don't know, maybe kids today look at us oldsters as obsoletes even in Math.
Rap music, anyone?
But bawling during the time of Metal Rock groups is really ridiculuous to pass for music. And, music or songs before Frank Sinatra's time should be banned from the airwaves!