129.701 in expanded form:
100 + 20 + 9 + (7 x 1/10) + (1 x 1/1000)
1 is in the hundreds place so 1 x 100 = 100
2 is in the tens place so 2 x 10 = 20
9 is in the ones place so 9 x 1 = 9
7 is in the tenths place so 7 x 1/10 = 0.7
1 is in the thousandths place so 1 x 1/1000 = 0.001