protected Matrix add_(Matrix m, Matrix destination) {
		if (!isSameLength(m))
			throw new IndexOutOfBoundsException("mxn do not equal this matrix");
		for (int i = 1; i <= this.m; i++) {
			for (int j = 1; j <= this.n; j++) {
				destination.insert(i, j, this.get(i, j) + m.get(i, j));
			}
		}
		return destination;
	}