Question

3 upon 7 minus 4 upon 9 + (minus 5) upon 21 + 2 upon 3

Answer 1

3/7- 4/9 +(-5/21+2/3)

3/7 - 4/9 -5/21 + 2/3

3/7 - 4/9 - 5×1 + 2×7 / 21

3/7 - 4/9 - 5 + 14 /21

3/7 -4/9 + 9/21

the sign has changed because - , + is '-'

and 9/21 can be reduced further so it will be

3/7 -4/9 + 3/7

now take the LCM of -4/9 and 3/7 , then the LCM will be 63

3/7 -4×7 + 3×9/ 63

3/7 -28 + 27/63

3/7 -1/63

here the sign is not changed bcz the value of negative sign is more than the positive

now LCM of 3/7 and -1/63 will be 63

3×9 - 1 × 1/63

27- 1/63

26/63

26/63 is the final answer