Question

To calculate 300-127, a student writes 127 + 3 = 130, 70 = 200, 100 = 300, 3 + 70 + 100 - 170.

Option 1: 130
Option 2: 200
Option 3: 300
Option 4: 170

Answer 1

The correct subtraction of 300 - 127 is actually 173. The method of adding up to reach the desired value provided a close estimate but is not the standard way of subtracting numbers. The proper approach involves aligning by place value and subtracting each place individually or directly subtracting second number from the first.

Step-by-step explanation:

The calculation process described in the student's question seems to involve breaking down the subtraction problem into simpler components that can be recombined to find the final result. However, the process got misinterpreted along the way. To correctly perform the subtraction 300 - 127, we need to subtract directly or use complementary additions to find the value.

Correct Approach

To start, we calculate 127 + 3 = 130. Next, because we want to reach 300, we look for what amount could be added to 130 to get 300. We can do this by subtracting 130 from 300: 300 - 130 = 170. Therefore, the correct difference between 300 and 127 is indeed 170, as that is the amount needed to add to 127 to result in 300.

Alternatively, if we proceed by breaking the subtraction into parts as the student seemed to intend, we would align the numbers by place value and subtract accordingly:

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So the correct answer is 173, and not 170 as the method might imply.