(NewsNation) — Control of the U.S. House is up for grabs on election night and the simple math favors Republicans. It’s not just polling. Democrats are defending more seats in tough districts than Republicans are.

Only a small handful of really competitive races, of which there are dozens, need to flip from blue to red for the GOP to control the House.

Democrats’ current majority in the House sits at just five seats.

It’s a historically small margin which, according to the polls, Democrats are expected to lose this Tuesday.

Out of 435 House races 212 either lean or are likely to be in Republican hands. 188 are more likely in Democratic control, according to Cook Political Report.

Decision Desk HQ gives Republicans a 79% chance to win control of the House after the midterms.

That leaves roughly 35 toss-up seats up for grabs, which will decide who controls the House. Of those 35 toss-ups, Republicans only need to win six to control the House, Democrats would need to win 30.

In California, there are a handful of tight races in Orange and San Diego counties, typically swing district territory where Democrats have performed well in recent years.

Democrats Mike Levin and Katie Porter’s seats are dead heats as are Republicans David Valadao and Mike Garcia.

In New York, redistricting and retirements have left some Democratic seats wide open in Long Island and in the suburbs north of New York City. Five key races there could decide House control. Including that of Democrat Sean Patrick Maloney who is battling for his career. Ironically, the congressman in charge of the DCCC, responsible for getting Democrats re-elected.

Polls in the battleground state of Nevada show razor-thin races for governor, Senate and House races. Nevada only has four U.S. House seats, and three of them are extremely tight. All are in Democrat’s hands but all are within Republican’s reach.

And finally, to the ever-important Pennsylvania with a crucial governor and Senate race. The Keystone State also features three toss-up House races where incumbent Democrats Matt Cartwright and Susan Wild defend their seats.

It is a fact that the party in control of the White House tends to lose House seats in midterm years. But just as important as who controls the House is the margin of victory. If Republicans end up winning back a majority, but it’s a small majority, it’ll be harder to pass any legislation. Same for Democrats, if they defy the odds and keep a majority, a small majority will still handicap them when it comes to actually getting things done.