If 5×9=144;7×8=151:4×6=102, then 2×5=?
1) +1-2+3-4+5-6+7-8+9-10
2) -931-723+941-265
Find the number from each of the following expanded forms:
(a) 8 × 104 + 6 × 103 + 0 × 102 + 4 × 101 + 5 × 100
(b) 4 × 105 + 5 × 103 + 3 × 102 + 2 × 100
(c) 3 × 104 + 7 × 102 + 5 × 100
(d) 9 × 105 + 2 × 102 + 3 × 101