Use multiplication to tell "how many." Multiply by 2 using the grouping of objects. Explore multiplication to help us tell "how many." Multiply by 2 using the grouping of objects and arrays. Connect ...
19 is only 1 away from 20, so you prefer to start by multiplying 20 times 5, which equals 100. Then we need to take away a squadron of 5, because there are actually only 19 squadrons, not 20. 100 take ...