The problem is deeper than just doing unit conversions, or getting used to decimal multiples and submultiples.
The problem is that the US metric system is physically incoherent, as the base units are Length, Time and Force.
1 Lb is a unit of force, not of mass as it is 1 kg...
The SI unit, instead, is physically coherent, as the base units are length, time and mass.
Using an incoherent measurement system requires to "patch" physical formulas adding a dummy factor, usually called gc, and numerically equal to the Earth's gravity acceleration for converting force to mass.
Example:
The first Newton law says that the force applied to a body is equal to the product of the mass of the body multiplied by its acceleration.
In SI we write this as:
F=M*a.
Force is in Newton, mass is in kg and acceleration is in m/(s^2).
In the US system, force is in lb-force and acceleration is in feet/(s^2).
If also the mass is expressed in lb-mass, the above formula becomes dimensionally wrong.
You fix it this way:
F=M*a/gc
The units of gc is lb-mass*m/(s^2)/lb-force and its numerical value is the same as g=32.17405 ft/s^2.
You can understand how the need of writing the formulas differently is a mess.
So it is not just matter of converting lb in kg, or ft to m, which is trivial.
All the formulas in your textbook need to be revised, for making them physically coherent...