The true statements from your list are:
II. One reason computers were first developed was to do mathematical computations faster. III. Some modern computers include laptops, cell phones, and tablets. IV. Computers are able to perform tasks by using logic.
Statement I is false because early computing devices, such as the abacus and mechanical calculators, existed long before the 1940s. The electronic computers we think of today started to emerge in the 1940s, but computing in some form has been around for centuries.