Answer:
For question 24 the answer: In this sum, the greater number is 9, however, 9 doesn't have a negative sign, which means that the answer to this sum should be a positive 3 not negative
And for question 25 the answer: In this sum, we should use a known rule, a negative number plus a negative number is a negative one, which means that we should be adding -10 and -10 to get a -20.