All the attacks took place in Borno state, which has been among the areas most targeted in recent years by Boko Haram.
The deadliest happened around 5 p.m. (noon ET) Tuesday, when gunmen barricaded a highway linking Maiduguri, the Borno state capital, and Damaturu, the capital of neighboring Yobe state, and killed more than 20 motorists, federal lawmaker Mohammed Sanda said.
These attackers -- who Sanda said were Boko Haram militants -- then stormed the village of Ngamdu, setting homes on fire and spurring residents to flee, said the lawmaker said.
Boko Haram gunmen also ambushed and killed eight people traveling on a lorry, or large truck, from Maiduguri to the town of Baga, which is on the shore of Lake Chad, local vigilantes said.
Those on the vehicle had fled Baga due to the militant group's bloody advance and were heading home after Nigeria's military reclaimed their hometown. They were about 2.5 miles (4 kilometers) away when gunmen attacked around 4 p.m. Tuesday, shot the eight passengers in the head, then fled into the nearby bush, according to the vigilantes.
And in Damasak -- a town taken by Boko Haram last November that's just a few miles away from Niger -- dozens of militants burned structures and killed at least five people, residents said. This attack came shortly after Chadian troops, which had warned people to evacuate, pulled out of Damasak.
Nigeria's years-long fight against Boko Haram
Such violence has plagued this region for years, with Boko Haram proving time and again its willingness to kill innocent civilians as well as government officials and Nigerian troops.
In addition to sporadic raids, the reviled terrorist group has bombed marketplaces, churches and mosques and other public gathering spots and conducted mass kidnappings -- the most notorious being last year's abduction of more than 200 girls from a school in the northeastern city of Chibok
. Those girls' fate remains a mystery.
Boko Haram's aim is to impose a stricter enforcement of Sharia law across Nigeria, which is split between a majority Muslim north and a mostly Christian south. And it has struck in many places, though the northeast part of the African nation has been hit most relentlessly.
While claiming some victories, Nigeria's military hasn't been able to stifle this onslaught. In fact, attacks have spiked since the May presidential inauguration of Muhammadu Buhari, a former general who defeated incumbent Goodluck Jonathan in Nigeria's first democratic transition of power.
Earlier this week, Buhari replaced all service chiefs -- from the defense, army, navy, air and defense intelligence departments, along with the national security adviser -- who'd worked for his predecessor, an expected though still potentially significant move in the country's fight against Boko Haram.
What the new president will do next isn't known, beyond his promise to move Nigeria's military command center to Maiduguri.