Question

14. Find the Error Hiroshi is determining -42 – (-37). Find his

mistake and correct it.
C - 42 - (-37) = 42-37

Answer 1

Hiroshi's error was not having changed the sign of the number 37 by removing the parentheses and placing -37 instead of +37.

Explanation:

we have

Hiroshi's work

`42-(-37)=42-37=5`

Remember that

a negative number is just a positive number multiplied by -1

and (-1)(-1)=+1

so

Correct work

`42-(-37)`

`42-(-1)(37)`

`42-(1)(-1)(37)`

`42+(-1)(-1)(37)`

`=42+37=79`

therefore

Hiroshi's error was not having changed the sign of the number 37 by removing the parentheses and placing -37 instead of +37.