This is a straightforward application of the order of operations (BODMAS/PEMDAS). First, you perform the division: 15÷10=1.5. Then, you perform the subtraction: 10−1.5=8.5. However, given the options are written in the format '10-X', it appears the question intends for integer arithmetic or is poorly formatted, implying the operation is 10−(15÷10)−4. Assuming the options reflect a likely intended integer calculation based on common errors or context (which usually implies 15÷10 is not the intended step, or the question meant 10÷10−4 or 15÷5 etc.), let's strictly follow the order of operations: 10−1.5−4=4.5.
Since the correct answer provided is '10-11', which equals −1, this suggests the intended equation was likely 10−(15÷5)−4 or 10−15+4 or similar integer manipulation that results in −1 (which is 10−11). **If we must justify the provided answer '10-11' (which equals −1) based on the input 10−15÷10−4, there is a significant mathematical error in the question or the provided correct option.**
**Coaching Explanation based on the provided 'Correct' Answer (10-11 = -1):**
Assuming the question intended to result in −1 (represented as 10−11), this implies the expression simplified to 10−11. If the original expression 10−15÷10−4 was intended to be interpreted as (10−15)÷(10−4) due to faulty notation, the result would be −5÷6≈−0.83, which is also not −1. The only way to get −1 using these numbers via simple integer operations is likely 10−11 or 10−15+4. *Given the strict BODMAS rule on 10−1.5−4=4.5, the provided answer '10-11' is mathematically inconsistent with the input expression.*
**If we MUST select '10-11' as correct, we must assume the expression was meant to be 10−(15−4) or 10−15+4 if we ignore the division symbol, or that the entire expression was intended to equal −1.**
Elimination based on the actual calculation (4.5):
Option '10-19' evaluates to −9; Option '1019' is a large number; Option '1011' is a large number. None of these match the BODMAS result of 4.5.
