Might be 1? Because it is 100 each
The Order of magnitude for the population of the world is not five
1.) 3+2=? ?=5 brothers 2.) 54+9=? ?=63 students 3.) 15-9=? ?=4
4.) 60-20=? ?=40 children 5.) 50-15=? ?=35 trees 6.) 14+4=? ?=18 times
Don't know why you needed help with this but ok.