Daughter is in 5th grade and I have no idea how to solve this math problem!
5 3/4 – 6 3/4
Obv you cannot subtract 5 from 6. You also can’t borrow the 3 from the 5 and make it a new mixed number. What do you borrow from? I’ve googled and seriously cannot figure this out.
In: 0
It is -1.
5×4+3 makes the first number 23/4
6×4+3 makes the second 27/4
23/4 – 27/4 = -4/4 = -1
The denominator 4, times 5, is 20, plus the numerator 3, and you have 23/4
The denominator 4, times 6, is 24, plus the numerator 3, and you have 27/4
23/4 – 27/4 = -4/4, or -1
All these answers are kinda complicated.
Ignore the fractions entirely.
5-6=-1
3/4-3/4=0
So answer is just -1
If the denominators were different (from each other) then maybe you need the more complex methods. But math is all about knowing which shortcuts to use and when.
> 5 3/4 – 6 3/4
5.75 – 6.75
> Obv you cannot subtract ~~5~~ [6] from ~~6~~ [5].
Yes you can, the answer is -1.
> You also can’t borrow the 3 from the 5 and make it a new mixed number.
Mixed numbers only belong in cooking & construction. Convert to an improper fraction:
5 3/4 = 23/4
6 3/4 = 27/4
(23-27)/4 = -4/4 = -1
If the bottoms weren’t both a 4, you’d have to convert to get the same bottom, or to a decimal.
_____
Example:
4 2/3 – 7 3/4
4 2/3 = 14/3
7 3/4 = 31/4
Bottoms aren’t the same, so find a multiple of 3 that is also a multiple of 4, which would 12.
14/3 = 56/12
31/4 = 93/12
(56-93)/12 = -37/12 ≈ -3.10
Do double check in approximate decimal form:
4 2/3 ≈ 4.67
7 3/4 = 7.75
4.67 – 7.75 ≈ -3.10
While many people have explained the general method of converting mixed numerals to a common base , this particular problem is much easier.
5 and 3/4 minus 6 and 3/4
The fractions are the same!
( 5 + 3/4 ) – ( 6 + 3/4 )
5 + 3/4 – 6 – 3/4
(3/4 – 3/4) + 5 – 6
0 + 5 – 6
5 – 6
Answer is -1 without really needing to understand fractions at all.
And it’s often good to check the results of an algorithm with common sense — when adding or subtracting mixed numbers check if the result is close what you expect the answer to be.
In addition to what the other people said, your English is incorrect here. We are trying to subtract 6 from 5, not the other way around.
With learning fractions, I recommend drawing it out on paper or doing it visually how you prefer. I’ll use pieces of pizza as an example.
5 3/4, so five whole pizzas and (in math, you say “and” where a decimal point would go, the fraction is smaller than one) three quarters of a pizza. To get the total amount of slices, you see that each one has 4 slices, the denominator (bottom number).
5 full pizzas with 4 slices each gives you 20 slices. You have an incomplete pizza, so you add those slices, from the number called the numerator on top, to the 20 you have, giving you 23 slices. (5 x 4 + 3) / 4 = 23/4, which is the same as 5 3/4.
So do the same for 6 3/4. 6 whole pizzas with 4 slices, one pizza with 3 out of 4. 6 times 4 slices is 24, plus 3 is 27.
*Okay, this question is confusing and I get why you’re having problems. I wonder if it’s a typo. Why are they doing positive and negative fractions while teaching basics at that level? I forget what grades these started.*
So now you have 27/4. 23/4 – 27/4. Both lower numbers, denominators, are the same, so you can subtract 27 from 23. That gives you -4 (negative 4) on the numerator, 4 on the denominator. They cancel each other out, 4/4 is one whole pizza, so it’s equal to 1. The negative is carried with the division, giving you -1 (negative one) for the answer.
I’d honestly ask if they wrote the question correctly.
I’m assuming we can read this as (5 + 3/4) – (6 + 3/4) instead of (5 * 3/4) – (6 + 3/4).
If so, it’s basically 5 + 3/4 – 6 – 3/4, which results in 5 – 6 = -1.
Or, you go (5 x 4/4 + 3/4) – (6 x 4/4 + 3/4) = (20/4 + 3/4) – (24/4 + 3/4) = 23/4 – 27/4 = -4/4 = -1.
I’ve always found “tips and tricks” in maths can be more confusing when you can actually understand the maths.
You have “five and three quarters” minus “six and three quarters”. You can deal with the fractions part separately from the whole numbers part, so you have: (5 – 6) + (3/4 – 3/4). The fractions part is easy, it’s just 0, and 5-6 is -1.
the thing to remember is that there is an implied ‘+’ between the whole number and the fraction.
5 ¾ means 5 whole and three quarters of a whole. You could write 5 + 3/4 to make it clearer, but usually we leave out the plus and treat the sum as number itself. We treat them like we would the number 5.75.
You can write your problem is: `5 + 3/4 – (6 + 3/4)` (the brackets are important because you subtract 6 and three quarters and don’t subtract 6 and then add three quarters.)
You can also write that as `5 + 3/4 – 6 – 3/4` or as `5 – 6 + 3/4 – 3/4` or `(5 – 6) + (3/4 – 3/4)` which works out to `-1 + 0 = -1`
You can also do it a number of different ways, which one is the one you are supposed to use here, depends on what your daughter last learned.
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