Replace each ? with the symbol = or ≠ to make the statement true. a. 54 ? 53 b. 8 ? 4 + 4 c. 23 + 6 ? 6 + 23 d. 64 ? 99

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

How do i multiply two digit numbers

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.