Defendants contend the trial court erred in granting plaintiffs’ motion for summary judgment and in denying defendants’ motion to dismiss pursuant to G.S. 1A-1, Rule 12(b)(6). We disagree.
[1] On a motion for summary judgment, the moving party has the burden of showing (i) the lack of a triable issue of fact and (ii) that he is entitled to judgment as a matter of law. Moore v. Crumpton, 306 N.C. 618, 295 S.E. 2d 436 (1982). The record discloses that the essential facts in this case are not in dispute. The question before the trial court was whether plaintiff Lee, as Executor, properly distributed the residuary estate under the Will of Taft M. Bass.
The primary object in interpreting a will is to give effect to the intention of the testator. Misenheimer v. Misenheimer, 312 N.C. 692, 325 S.E. 2d 195 (1985). This intention will be given effect unless it violates some rule of law or is contrary to public policy. Pittman v. Thomas, 307 N.C. 485, 299 S.E. 2d 207 (1983). This intent is to be gathered from a consideration of the will from its four corners. Where the intent of the testator is clearly expressed in plain and unambiguous language, there is no need to resort to the general rules of construction for an interpretation; rather, the will is to be given effect according to its obvious intent. Price v. Price, 11 N.C. App. 657, 182 S.E. 2d 217 (1971).
The interpretation of a will’s language is a matter of law. Wachovia v. Wolfe, 243 N.C. 469, 91 S.E. 2d 246 (1956).
In this case, the language used by the testator manifests his intention to divide the residuary estate into three equal shares with the widow’s cash distribution to be offset by the value of the marital home. We agree with Judge Smith’s conclusion “that in no event was either defendant entitled to more than one-third of the value of the residuary estate . . . .”
The only way to effect the distribution intended by the testator is to add the value of the homeplace to the residuary estate before deducting that value from Mrs. McCollum’s share. Utilizing this method, each defendant would receive $104,758.90 cash, and Mrs. McCollum would receive $36,758.90 cash plus the value of the $68,000.00 house for a total of $104,758.90. In this *376manner, each beneficiary would receive exactly one-third of the value of the residuary estate. Although the house clearly did not pass under the residuary estate, the value of the house is an essential component of the equation to balance the actual distribution of the residuary estate. Under the method by which Executor Lee distributed the estate, each defendant received an amount well in excess of his one-third of the residuary estate. The intent of a testator should not be circumvented by error in mathematical computations. Therefore, we hold plaintiffs motion for summary judgment was properly granted where they showed a lack of a triable issue of fact and that an error in the method of calculation caused the Executor to make an erroneous disbursement under the will.
[2] Defendants further contend that plaintiffs are barred under theories of settlement, waiver, release, ratification and estoppel. Each of these defenses requires some showing that the person against whom they are asserted had knowledge of the true facts underlying the claim. Defendants offered no affidavits or forecast of evidence suggesting that on 3 August 1983, Mrs. McCollum knew of her claim to additional funds or intended to abandon or relinquish such a claim. Because the record is void of any evidence that Mrs. McCollum knew at the time of distribution that the method of calculation did not comport with the terms of the testator’s will, all these defenses are unavailing to defendants.
[3] Defendants’ contention that the trial court erred in denying their motion to dismiss filed pursuant to G.S. 1A-1, Rule 12(b)(6) is premised on the theory that the mistake was one of law rather than of fact and that defendants would be prejudiced by failing to return the money. In our view, the mistake in calculation was one of fact, not of law, and plaintiff executor clearly stated a cause of action upon which relief could be granted. See Bank v. McManus, 29 N.C. App. 65, 223 S.E. 2d 554 (1976); Lyle v. Siler, 103 N.C. 261, 9 S.E. 491 (1889). Further, when matters outside the pleadings are considered on a motion to dismiss, the motion is converted to one for summary judgment and is disposed of in the manner stated in Rule 56. Fowler v. Williamson, 39 N.C. App. 715, 251 S.E. 2d 889 (1979).
[4] Although not raised in the briefs, we note that plaintiff Lee individually and Lawyers Mutual Liability Insurance Company *377lack standing and are not proper parties to bring an action against beneficiaries who have benefited from a wrongful or incorrect disbursement under a will. When the estate is open, an action to recover assets of an estate is properly prosecuted by the personal representative as the fiduciary responsible for the assets of the estate. A devisee is liable to refund money which has been paid to him by the executor under a mistake of fact, and repayment of the amount wrongfully paid may be enforced against him in a suit by the executor. 31 Am. Jur. 2d Executors and Administrators §§ 587-588 (1967). Once the estate has collected any wrongful disbursements, the executor must properly distribute these proceeds. G.S. 28A-22-1. Because Judge Smith correctly ordered that the excess disbursements be “returned] forthwith to Harry M. Lee as Executor of the Estate of Taft M. Bass . . . and that said monies so received by said Executor be properly distributed by him,” the presence of Lawyers Mutual in this ease was not prejudicial to the successful prosecution of this action.
The judgment appealed from is
Affirmed.
Chief Judge Hedrick and Judge Webb concur.