So for the first one, you'd round round 32 down to 30, and 79 up to 80. The new equation is 30×80. 3×8=24, then add the zeroes to make 2400. For the second one, round 95 up to 100, and 24 down to 20. 20×100=2000. The third 71 to 70, 48 to 50. 70×50=3500. The fourth, 89 to 90, 50 stays the same, 90×50=4500. Fifth, 21 to 20, 16 to 20, 20×20=400. Sixth 99 to 100, 91 to 90, 100×90=9000.
1: 2400
2:2000
3:3500
4: 4500
5: 400
6: 9000
