We can use casework to solve this question.
1*1 rectangles: 12
1*2 rectangles: 9
1*3 rectangles: 6
1*4 rectangles: 3
2*1 rectangles: 8
2*2 rectangles: 6
2*3 rectangles: 4
2*4 rectangles: 2
3*1 rectangles: 4
3*2 rectangles: 3
3*3 rectangles: 2
3*4 rectangles: 1
So, the answer to this question is 12+9+6+3+8+6+4+2+4+3+2+1=60.
We can use casework to solve this question.
1*1 rectangles: 12
1*2 rectangles: 9
1*3 rectangles: 6
1*4 rectangles: 3
2*1 rectangles: 8
2*2 rectangles: 6
2*3 rectangles: 4
2*4 rectangles: 2
3*1 rectangles: 4
3*2 rectangles: 3
3*3 rectangles: 2
3*4 rectangles: 1
So, the answer to this question is 12+9+6+3+8+6+4+2+4+3+2+1=60.